Comparison of cases of and death from typhoid in 1898 and 1911. What have we learned about combating typhoid since 1898?
During this period there were 49 cases of typhoid and 19 deaths in the near-by city of San Antonio. But in camp, where vaccination for typhoid was required, all were practically immune. In the army at large, since typhoid vaccination has been practiced, 1908-1909, the death rate from typhoid has dropped from 2.9 per 1000 to .03 per 1000, a wonderful record when we remember that during the Spanish-American War 86 per cent of the deaths in the army were from typhoid fever.
How the Board of Health fights Tuberculosis.—Tuberculosis, which a few years ago killed fully one seventh of the people who died from disease in this country, now kills less than one tenth. This decrease has been largely brought about because of the treatment of the disease. Since it has been proved that tuberculosis if taken early enough is curable, by quiet living, good food, and plenty of fresh air and light, we find that numerous sanitaria have come into existence which are supported by private or public means. At these sanitaria the patients live out of doors, especially sleep in the air, while they have plenty of nourishing food and little exercise. The department of health of New York City maintains a sanitarium at Otisville in the Catskill Mountains. Here people who are unable to provide means for getting away from the city are cared for at the city's expense and a large percentage of them are cured. In this way and by tenement house laws which require proper air shafts and window ventilation in dwellings, by laws against spitting in public places, and in other ways, the boards of health in our towns and cities are waging war on tuberculosis.
The best cures for tuberculosis are rest, plenty of fresh out-of-door air, and wholesome food.
A sanitarium for tuberculosis. Notice the outdoor sleeping rooms.
Ex-President Roosevelt said, in one of his latest messages to Congress:—
"There are about 3,000,000 people seriously ill in the United States, of whom 500,000 are consumptives. More than half of this illness is preventable. If we count the value of each life lost at only $1700 and reckon the average earning lost by illness at $700 a year for grown men, we find that the economic gain from mitigation of preventable disease in the United States would exceed $1,500,000,000 a year. This gain can be had through medical investigation and practice, school and factory hygiene, restriction of labor by women and children, the education of the people in both public and private hygiene, and through improving the efficiency of our health service, municipal, state, and national."
Work of the Division of School and Infant Hygiene.—Besides the work of the division of infectious disease, the division of sanitation, which regulates the general sanitary conditions of houses and their surroundings and the division of inspection, which looks after the purity and conditions of sale and delivery of milk and foods, there is another department which most vitally concerns school children. This is the division of school and infant hygiene. The work of this department is that of the care of the children of the city. During the year 1912, 279,776 visits were made to the homes of school children of the city of New York by inspectors and nurses. Besides this, thousands of children in school were cared for and aided by the city.
Adenoids.—Many children suffer needlessly from adenoids,—growths in the back of the nose or mouth which prevent sufficient oxygen being admitted to the lungs. A child suffering from these growths is known as a "mouth breather" because the mouth is opened in order to get more air. The result to the child may be a handicap of deafness, chronic running of the nose, nervousness, and lack of power to think. His body cells are starving for oxygen. A very simple operation removes this growth. Coöperation on the part of the children and parents with the doctors or nurses of the board of health will do much in removing this handicap from many young lives.
Eyestrain.—Another handicap to a boy or girl is eyestrain. Twenty-two per cent of the school children of Massachusetts were recently found to have defects in vision. Tests for defective eyesight may be made at school easily by competent doctors, and if the child or parent takes the advice given to correct this by procuring proper glasses, a handicap on future success will be removed.
Decayed Teeth.—Decayed teeth are another handicap, cared for by this division. Free dental clinics have been established in many cities, and if children will do their share, the chances of their success in later life will be greatly aided. Boys and girls, if handicapped with poor eyes or teeth, do not have a fair chance in life's competition. In a certain school in New York City there were 236 pupils marked "C" in their school work. These children were examined, and 126 were found to have bad teeth, 54 defective vision, and 56 other defects, as poor hearing, adenoids, enlarged tonsils, etc. Of these children 185 were treated for these various difficulties, and 51 did not take treatment. During the following year's work 176 of these pupils improved from "C" to "B" or "A", while 60 did not improve. If defects are such a handicap in school, then what would be the chances of success in life outside.
In conclusion: this department of school hygiene deserves the earnest aid of every young citizen, girl or boy. If each of us would honestly help by maintaining quarantine in the case of contagious disease, by observing the rules of the health department in fumigation, by acting upon advice given in case of eyestrain, bad teeth, or adenoids, and most of all by observing the rules of personal hygiene as laid down in this book, the city in which we live would, a generation hence, contain stronger, more prosperous, and more efficient citizens than it does to-day.
Reference Books
elementary
Hunter, Laboratory Problems in Civic Biology. American Book Company.
Davison, The Human Body and Health. American Book Company.
Gulick Hygiene Series, Town and City. Ginn and Company.
Hough and Sedgwick, The Human Mechanism, Part II. Ginn and Company.
Overton, General Hygiene. American Book Company.
Richards, Sanitation in Daily Life. Whitcomb and Barrows.
Richmond and Wallach, Good Citizenship. American Book Company.
Ritchie, Primer of Sanitation. World Book Company.
Sharpe, Laboratory Manual of Biology, pages 320-334. American Book Company.
advanced
Allen, Civics and Health. Ginn and Company.
Chapin, Municipal Sanitation in the United States. Snow and Farnham.
Chapin, Sources and Modes of Infection. Wiley and Sons.
Conn, Practical Dairy Bacteriology. Orange Judd Company.
Hough and Sedgwick, The Human Mechanism. Part II. Ginn and Company.
Hutchinson, Preventable Diseases. The Houghton, Mifflin Company.
Morse, The Collection and Disposal of Municipal Waste. Municipal Journal and Engineer.
Overlock, The Working People, Their Health and How to Protect It. Mass. Health Book Publishing Co.
Price, Handbook of Sanitation. Wiley and Sons.
Tolman, Hygiene for the Worker. American Book Company.
reports, etc.
American Health Magazine.
Annual Report of Department of Health, City of New York (and other cities).
Bulletins and Publications of Committee of One Hundred on National Health.
School Hygiene, American School Hygiene Association.
Grinnell, Our Army versus a Bacillus. National Geographic Magazine.
XXV. SOME GREAT NAMES IN BIOLOGY
If we were to attempt to group the names associated with the study of biology, we would find that in a general way they were connected either with discoveries of a purely scientific nature or with the benefiting of man's condition by the application of the purely scientific discoveries. The first group are necessary in a science in order that the second group may apply their work. It was necessary for men like Charles Darwin or Gregor Mendel to prove their theories before men like Luther Burbank or any of the men now working in the Department of Agriculture could benefit mankind by growing new varieties of plants. The discovery of scientific truths must be achieved before the men of modern medicine can apply these great truths to the cure or prevention of disease. Since we are most interested in discoveries which touch directly upon human life, the men of whom this chapter treats will be those who, directly or indirectly, have benefited mankind.
The Discoverers of Living Matter.—The names of a number of men living at different periods are associated with our first knowledge of cells. About the middle of the seventeenth century microscopes came into use. Through their use plant cells were first described and pictured as hollow boxes or "cells." But it was not until 1838 that two German friends, Schleiden and Schwann by name, working on plants and animals, discovered that both of these forms of life contained a jellylike substance that later came to be called protoplasm. Another German named Max Schultz in 1861 gave the name protoplasm to all living matter, and a little later still Professor Huxley, a famous Englishman, friend and champion of Charles Darwin, called attention to the physical and chemical qualities of protoplasm so that it came to be known as the chemical and physical basis of life.
Prof. Tyndall's experiment to show that if air containing germs is kept from organic substances, such substances will not decay. The box is sterilized; likewise the tubes (t) containing nutrients. Air is allowed to enter by the tubes (u), which are so made that dust is prevented from entering. A thermometer (th) records the temperature. The substances in the tubes do not decay, no matter how favorable the temperature.
Life comes from Life.—Another group of men, after years of patient experimentation, worked out the fact that life comes from other life. In ancient times it was thought that life arose spontaneously; for example, that fish or frogs arose out of the mud of the river bottoms, and that insects came from the dew or rotting meat. It was believed that bacteria arose spontaneously in water, even as late as 1876, when Professor Tyndall proved by experiment the contrary to be true.
As early as 1651 William Harvey, the court physician of Charles I of England, showed that all life came from the egg. It was much later, however, that the part played by the sperm and egg cell in fertilization was carefully worked out. It is to Harvey, too, that we owe the beginnings of our knowledge of the circulation of the blood. He showed that blood moved through tubes in the body and that the heart pumped it. He might be called the father of modern physiology as well as the father of embryology. A long list of names might be added to that of Harvey to show how gradually our knowledge of the working of the human body has been added to. At the present time we are far from knowing all the functions of the various parts of the human engine, as is shown by the number of investigators in physiology at the present time. Present-day problems have much to do with the care of the human mechanism and with its surroundings. The solution of these problems will come from applying the sciences of hygiene, preventive medicine, and sanitation.
In the preceding chapters of this book we have learned something about our bodies and their care. We have found that man is able within limitations to control his environment so as to make it better to live in. All of the scientific facts that have been of use to man in the control of disease have been found out by men who have devoted their lives in the hope that their experiments and their sacrifices of time, energy, and sometimes life itself might make for the betterment of the human race. Such men were Harvey, Jenner, Lister, Koch, and Pasteur.
Edward Jenner, the discoverer of vaccination.
Edward Jenner and Vaccination.—The civilized world owes much to Edward Jenner, the discoverer of vaccination against smallpox. Born in Berkeley, a little town of Gloucestershire, England, in 1749, as a boy he showed a strong liking for natural history. He studied medicine and also gave much time to the working out of biological problems. As early as 1775 he began to associate the disease called cowpox with that of smallpox, and gradually the idea of inoculation against this terrible scourge, which killed or disfigured hundreds of thousands every year in England alone, was worked out and applied. He believed that if the two diseases were similar, a person inoculated with the mild disease (cowpox) would after a slight attack of this disease be immune against the more deadly and loathsome smallpox. It was not until 1796 that he was able to prove his theory, as at first few people would submit to vaccination. War at this time was being waged between France and England, so that the former country, usually so quick to appreciate the value of scientific discoveries, was slow to give this method a trial. In spite of much opposition, however, by the year 1802, vaccination was practiced in most of the civilized countries of the world. At the present time the death rate in Great Britain, the home of vaccination, is less than .3 to every 1,000,000 living persons. This shows that the disease is practically wiped out in England. An interesting comparison with these figures might be made from the history of the disease in parts of Russia where vaccination is not practiced. There, thousands of deaths from smallpox occur annually. During the winter of 1913-1914 an epidemic of smallpox with more than 250 cases broke out in the city of Niagara Falls. This epidemic appears to be due to a campaign conducted by people who do not believe in vaccination. In cities and towns near by, where vaccination was practiced, no cases of smallpox occurred. Naturally if opposition to vaccination is found nowadays, Jenner had a much harder battle to fight in his day. He also had many failures, due to the imperfect methods of his time. The full worth of his discovery was not fully appreciated until long after his death, which occurred in 1823.
Louis Pasteur.
Louis Pasteur.—The one man who, in biological science, did more than any other to directly benefit mankind was Louis Pasteur. Born in 1822, in the mountains near the border of northeastern France, he spent the early part of his life as a normal boy, fond of fishing and not very partial to study. He inherited from his father, however, a fine character and grim determination, so that when he became interested in scientific pursuits he settled down to work with enthusiasm and energy.
At the age of twenty-five he became well known throughout France as a physicist. Shortly after this he became interested in the tiny plants we call bacteria, and it was in the field of bacteriology that he became most famous. First as professor at Strassburg and at Lille, later as director of scientific studies in the École Normale at Paris, he showed his interest in the application of his discoveries to human welfare.
In 1857 Pasteur showed that fermentation was due to the presence of bacteria, it having been thought up to this time that it was a purely chemical process. This discovery led to very practical ends, for France was a great wine-producing country, and with a knowledge of the cause of fermentation many of the diseases which spoiled wine were checked.
In 1865-1868 Pasteur turned his attention to a silkworm disease which threatened to wipe out the silk industry of France and Italy. He found that this disease was caused by bacteria. After a careful study of the case he made certain recommendations which, when carried out, resulted in the complete overthrow of the disease and the saving of millions of dollars to the poor people of France and Italy.
The greatest service to mankind came later in his life when he applied certain of his discoveries to the treatment of disease. First experimenting upon chickens and later with cattle, he proved that by making a virus (poison) from the germs which caused certain diseases he could reduce this virus to any desired strength. He then inoculated the animals with the virus of reduced strength, giving the inoculated animals a mild attack of the disease, and found that this made them immune from future attacks. This discovery, first applied to chicken cholera, laid the foundation for all future work in the uses of serums, vaccines, and antitoxins.
Pasteur was perhaps the best known through his study of rabies. The great Pasteur Institute, founded by popular subscriptions from all over the world, has successfully treated over 22,000 cases of rabies with a death rate of less than 1 per cent. But more than that it has been the place where Roux, a fellow worker with Pasteur, discovered the antitoxin for diphtheria which has resulted in the saving of thousands of human lives. Here also have been established the principles of inoculation against bubonic plague, lockjaw, and other germ diseases.
Pasteur died in 1895 at the age of seventy-three, "the most perfect man in the realm of science," a man beloved by his countrymen and honored by the entire world.
Robert Koch.
Robert Koch.—Another name associated with the battle against disease germs is that of Robert Koch. Born in Klausthal, Hanover, in 1843, he later became a practicing physician, and about 1880 was called to Berlin to become a member of the sanitary commission and professor in the school of medicine. In 1881 he discovered the germ that causes tuberculosis and two years later the germ that causes Asiatic cholera. His later work has been directed toward the discovery of a cure for tuberculosis and other germ diseases. As yet, however, no certain cure seems to have been found.
Lister and Antiseptic Treatment of Wounds.—A third great benefactor of mankind was Sir Joseph Lister, an Englishman who was born in 1827. As a professor of surgery he first applied antiseptics in the operating room. By means of the use of carbolic acid or other antiseptics on the surface of wounds, on instruments, and on the hands and clothing of the operating surgeons, disease germs were prevented from taking a foothold in the wounds. Thus blood poisoning was prevented. This single discovery has done more to prevent death after operations than any other of recent time.
Modern Workers on the Blood.—At the present time several names stand out among investigators on the blood. Paul Ehrlich, a German born in 1854, is justly famous for his work on the blood and its relation to immunity from certain diseases. His last great research has given to the world a specific against the dread disease syphilis.
Another name associated with the blood is that of Elias Metchnikoff, a Russian. He was born in 1845. Metchnikoff first advanced the belief that the colorless blood corpuscles, or phagocytes, did service as the sanitary police of the body. He has found that there are several different kinds of colorless corpuscles, each having somewhat different work to do. Much of the modern work done by physiologists on the blood are directly founded on the discoveries of Metchnikoff.
Charles Darwin, the grand old man of biology.
Heredity and Evolution. Charles Darwin.—There is still another important line of investigation in biology that we have not mentioned. This is the doctrine of evolution and the allied discoveries along the line of heredity. The development or evolution of plants and animals from simpler forms to the many and present complex forms of life have a practical bearing on the betterment of plants and animals, including man himself. The one name indelibly associated with the word evolution is that of Charles Darwin.
Charles Darwin was born on February 12, 1809, a son of well-to-do parents, in the pretty English village of Shrewsbury. As a boy he was very fond of out-of-door life, was a collector of birds' eggs, stamps, coins, shells, and minerals. He was an ardent fisherman, and as a young man became an expert shot. His studies, those of the English classical school, were not altogether to his liking. It is not strange, perhaps, that he was thought a very ordinary boy, because his interest in the out-of-doors led him to neglect his studies. Later he was sent to Edinburgh University to study medicine. Here the dull lectures, coupled with his intense dislike for operations, made him determine never to become a physician. But all this time he showed his intense interest in natural history and took frequent part in the discussions at the meetings of one of the student zoölogical societies.
In 1828 his father sent him to Cambridge to study for the ministry. His three years at the university were wasted so far as preparation for the ministry were concerned, but they were invaluable in shaping his future. He made the acquaintance of one or two professors who were naturalists like himself, and in their company he spent many happy hours in roaming over the countryside collecting beetles and other insects. In 1831 an event occurred which changed his career and made Darwin one of the world's greatest naturalists. He received word through one of his professional friends that the position of naturalist on her Majesty's ship Beagle was open for a trip around the world. Darwin applied for the position, was accepted, and shortly after started on an eventful five years' trip around the world. He returned to England a famous naturalist and spent the remainder of his long and busy life producing books which have done more than those of any other writer to account in a satisfactory way for the changes of form and habits of plants and animals on the earth. His theories established a foundation upon which plant and animal breeders were able to work.
His wonderful discovery of the doctrine of evolution was due not only to his information and experimental evidence, but also to an iron determination and undaunted energy. In spite of almost constant illness brought about by eyestrain, he accomplished more than most well men have done. His life should mean to us not so much the association of his name with the Origin of Species or Plants and Animals under Domestication, two of his most famous books, but rather that of a patient, courteous, and brave gentleman who struggled with true English pluck against the odds of disease and the attacks of hostile critics. He gave to the world the proofs of the theory on which we to-day base the progress of the world. Darwin lived long enough to see many of his critics turn about and come over to his beliefs. He died on the 19th of April, 1882, at seventy-four years of age.
Associated with Darwin's name we must place two other co-workers on heredity and evolution, Alfred Russel Wallace, an Englishman who independently and at about the same time reached many of the conclusions that Darwin came to, and August Weissman, a German. The latter showed that the protoplasm of the germ cells (eggs and sperms) is directly handed down from generation to generation, they being different from the other body cells from the very beginning. In 1883 a German named Boveri discovered that the chromosomes of the egg and the sperm cell were at the time of fertilization just half in number of the other cells (see page 252) so that a fertilized egg was really a whole cell made up of two half cells, one from each parent. The chromosomes within the nucleus, we remember, are believed to be the bearers of the hereditary qualities handed down from parent to child. This discovery shows us some of the mechanics of heredity.
Applications to Plant and Animal Breeding.—Turning to the practical applications of the scientific work on the method of heredity, the name of Gregor Mendel, an Austrian monk, stands out most prominently. Mendel lived from 1822 until 1884. His work, of which we already have learned something (see page 258), remained undiscovered until a few years ago. The application of his methods to plant and animal raising are of the utmost importance because the breeder is able to separate the qualities he desires and breed for those qualities only. Another name we have mentioned with reference to plant breeding is Hugo de Vries, the Dutchman who recently showed that in some cases plants arise as new species by sudden and great variations known as mutations. And lastly, in our own California, Luther Burbank, by careful hybridizing, is making lasting fame with his new and useful hybrid plants.
References
Conn, Biology. Silver, Burdett & Co.
Darwin, Life and Letters of Charles Darwin. Appletons.
Galton, Hereditary Genius. London (1892).
Thompson, Heredity. John Murray, London England.
Wasmann, Problem of Evolution. Kegan Paul, Trench, Trübner and Co., London, E. C.
APPENDIX
A SUGGESTED OUTLINE FOR BIOLOGY BEGINNING IN THE FALL
LIST OF TOPICS
First Term
First week. Why study Biology? Relation to human health, hygiene. Relations existing between plants and animals. Relation of bacteria to man. Uses of plants and animals. Conservation of plants and animals. Relation to life of citizen in the city. Plants and animals in relation to their environment. What is the environment; light, heat, water, soil, food, etc. What plants take out of the environment. What animals take out of the environment. Dependence of plants and animals upon the factors of the environment. Laboratory: Study of a plant or an animal in the school or at home to determine what it takes from its environment.
Second week. Some Relations existing between Plants (Green) and Animals. Field trip planned to show that insects feed upon plants; make their homes upon plants. That flowers are pollinated by insects. Insects lay eggs upon certain food plants. Green plants make food for animals. Other relations. (Time allotment. One day trip, collecting, etc.; two days' discussion of trip in all its relations.) Make a careful study of the locality you wish to visit, have a plan that the pupils know about beforehand. Review and hygiene of pupil's environment, 2 days.
Third week. Study of a Flower, Parts Essential to Pollination Named. Adaptations for insect pollination worked out in laboratory. Study of bee or butterfly as an insect carrier of pollen. Names of parts of insect learned. Elementary knowledge of groups of insects seen on field trip. Bees, butterflies, grasshoppers, beetles, possibly flies and bugs. Drawing of a flower, parts labeled. Drawing of an insect, outline only, parts labeled. Careful study of some fall flower fitted for insect pollination with an insect as pollinating agent. Some examples of cross-pollination explained. Practical value of cross-pollination.
Fourth week. Living Plants and Animals Compared. Parts of plants, functions; organs, tissues, cells. Demonstration cells of onion or elodea. How cells form others. What living matter can do. Reproduction. Growth of pollen tube, fertilization. Development of ovule into seed. Fruits, how formed. Uses, to man.
Fifth week. What makes a Seed Grow. Bean seed, a baby plant, and food supply. Food, what is it? Organic nutrients, tests for starch, protein, oil. Show their presence in seeds.
Sixth week. Need for Foods. Germination of bean due to (a) presence of foods, (b) outside factors. What is done with the food. Release of energy. Examples of engine, plants, human body. Oxidation in body. Proof by experiment. Test for presence of CO2. Oxidation in growing plant, experiment. Respiration a general need for both plants and animals.
Seventh week. Need for Digestion. The corn grain. Parts, growth, food supply outside body of plant, how does it get inside. Digestion, need for. Test for grape sugar. Enzymes, their function. Action of diastase on starch.
Eighth week. What Plants take from the Soil, How they do This. Use of root. Influence of gravity and water. Why? Absorption a function. Root hairs. Demonstration. Pocket gardens, optional home work, but each pupil must work on root hairs from actual specimen. How root absorbs. Osmosis; what substances will osmose. Experiments to demonstrate this.
Ninth week. Composition of Soil. What root hairs take out of soil. Plant needs mineral matter to make living matter. Why? Nitrogen necessary. Sources of nitrogen, the nitrogen-fixing bacteria. Relation of this to man. Rotation of crops.
Tenth week. How Green Plants make Food. Passage of liquids up stem. Demonstration. Structure of a green leaf. Cellular structure demonstrated. Microscopic demonstration of cells, stoma, air spaces, chlorophyll bodies. Evaporation of water from green leaf, regulation of transpiration.
Eleventh week. Midterm Examinations. Sun a source of energy. Effect of light on green plants. Experimental proof. Starch made in green leaf. Light and air necessary for starch making. Proof. Protein making in leaf. By-products in starch making. Proof. Respiration.
Twelfth week. The Circulation and Distribution of Food in Green Plants. Uses of bark, wood, what part of stem does food pass down. Willow twig experiment. Summary of functions of living matter in plant. Forestry lecture. Economic uses of green plants. Reports.
Thirteenth week. Plants without Chlorophyll in their Relation to Man. Saprophytic fungi. Molds. Growth on bread or other substances. Conditions most favorable for growth. Favorite foods. Methods of prevention. Economic importance.
Fourteenth week. Yeasts in their Relation to Man. Experiments to show fermentation is caused by yeasts. Experiments to show conditions necessary for fermentation. The part played by yeasts in bread making, in wine making, in other industries. Structure of yeast demonstrated. Summary.
Fifteenth week. Experiments to show where Bacteria may be found and Conditions necessary to Growth Begun. Have cultures collected and placed in a warm room during the holidays. Suggested experiments are exposure to air of quiet room and room with persons moving, dust of floor, knife blade, etc.
Sixteenth, seventeenth, and eighteenth weeks. The Month of January should be Devoted to the Study of Bacteria in their General Relations to Man. Economically, both directly and indirectly. Especial emphasis placed on the nature and necessity of decay. Bacteria in relation to disease should also be emphasized. The experiments to be performed and the topics expected to be covered follow.
Conditions Favorable and Unfavorable for Growth of Bacteria. (Use bouillon cultures.) Effect of intense heat, sterile bouillon exposed to air, effect of boiling, effect of cold, effect of antiseptics (corrosive sublimate, carbolic acid, boric acid, formalin, etc.), effect of large amounts of sugar and salt and the relation of this to preserving, etc. Bring out practical application of principles demonstrated. Discuss sterilization in medicine and surgery, cold storage, canning, sterilization, e.g. laundries, etc., use of antiseptics, preserving by means of salt and sugar. Microscopic demonstration of bacteria. Methods of reproduction. Importance in causing organic decay, fixation of nitrogen, various useful forms in cheese making, butter ripening, etc. Harmfulness of bacteria as disease producers. Specific diseases discussed: tuberculosis, typhoid, infective colds, blood poisoning, etc. Vaccination. Antitoxins begun—continued after knowledge of human body is gained. Work of Lister and Pasteur.
Nineteenth and twentieth weeks. Review and Examinations.
Second Term
First week. The Balanced Aquarium. Carbon and nitrogen cycles. Balanced aquarium and hay infusion compared.
Second week. One Protozoan, Demonstration to show Changes in Shape, Response to Stimuli, Summary of Vital Processes in Cell. Food getting, digestion, assimilation, oxidation, excretion, growth, reproduction. Internal structure of protozoan. Protozoa as cause of disease.
Third week. General Survey of Animal Kingdom. Survey introduced by museum trip if possible. Protozoa, worm, insect, fish, mammal. Distinction between vertebrate and invertebrate. Character of mammalia. Division of labor emphasized. Man's place in nature.
Fourth week. Study of the Frog. Relation to habitat, adaptations for locomotion, food getting, respiration, comparison of frog and fish on latter point. Osmotic exchange of gases emphasized. Cell respiration.
Fifth week. Metamorphosis of Frog. Fertilization, cell division, and differentiation emphasized. Touch on plant and animal breeding. Function of chromosomes as bearers of heredity. Comparison of bird's egg and mammal embryo.
Sixth week. Factors in Breeding. 1. Variation. 2. Selection. 3. Heredity fixes variation. 4. Hybridizing. 5. Control of environment. Eugenics in relation to (a) crime, (b) disease, (c) genius. Continuity of germ plasm. Work of Darwin, Mendel, De Vries, Burbank.
Seventh week. A Brief Study of the Gross Structure of the Human Body. Skin, muscles, bones. Removal of lime from bone by HCl to show other substances and need for lime. Effect of posture, spinal curvature, fractures, sprains.
Eighth week. Need for Food. Nutritive value of food. Use of charts to show foods rich in carbohydrates, fats, proteins, minerals, water, refuse. The relation of age, sex, work, and environment to the food requirements. What is a cheap food. Price list of common foods at present time. Efforts of government to secure a cheap food supply for the people. Digestibility of foods.
Ninth week. How the Fuel Value of Food has been Determined. Meaning of calorie. The 100-caloric portion, its use in determining a daily or weekly dietary. Standard dietary as determined by Atwater. Comparison of standards of Chittenden and Voit with those of Atwater.
Tenth week. Study of Pupil's Dietary. Planning ideal meals. Individual dietaries for one day required from each pupil. Discussions and corrections. The family dietary. Relation to cost.
Eleventh week. Digestion. The digestive system in the frog and in man compared. Drawings of each. Glands and enzymes. Internal secretions and their importance. Demonstration of glandular tissues. Experiment to show digestion of starch in mouth.
Twelfth week. Digestion Continued. Digestion of white of egg by gastric juice. Digestion of starch with pancreatic fluid. Functions of pancreatic juice. Microscopic examination of emulsion. Reasons for digestion. Part played by osmosis. Demonstration of osmosis. Non-osmosis of non-digested foods, comparison between osmosable qualities of starch and grape sugar.
Thirteenth week. Absorption. Where and how foods are absorbed. The structure of a villus explained. Course taken by foods after absorption. Function of liver. Blood making the result of absorption. Composition of blood, red and colorless corpuscles, plasma, blood plates, antibodies. Microscopic drawing of corpuscles of frog's and man's blood.
Fourteenth week. Circulation of Blood. The heart and lungs of frog demonstrated. Heart of man a force pump, explain with use of force pump. Demonstration of beef's heart. Circulation and changes of blood in various parts of body. Work of cells with reference to blood made clear. Capillary circulation (demonstration of circulation in tadpole's tail or web of frog's foot).
Fifteenth week. Respiration and Excretion. Necessity for taking of oxygen to cells and removal of wastes from cells. Part played by blood and lymph. Mechanics of breathing (use of experiments). Changes of air and blood in lungs (experiments). Best methods of ventilation (experiments). Elimination of wastes from blood by lungs, skin, and kidneys. Cell respiration.
Sixteenth week. Hygiene of Organs of Excretion, especially care of skin. The general structure and functions of the central nervous system. Sensory and motor nerves. Reflexes, instincts, habits. Habit formation, importance of right habits. Rules for habit formation. Habit-forming drugs and other agents. Lecture.
Seventeenth, eighteenth, nineteenth weeks. Civic Hygiene and Sanitation. Hygiene of special senses, eye and ear. A well citizen an efficient citizen. Public health is purchasable. Improvement of environment a means of obtaining this. Civic hygiene and sanitation. Cleaning up neighborhood, inquiry into home and street conditions. Fighting the fly. Conditions of milk and water supply. Relation of above to disease. Work of Board of Health, etc. Review and Examinations.
SUGGESTED SYLLABUS FOR COURSE BEGINNING FEBRUARY 1 AND ENDING THE FOLLOWING JANUARY
First Term
First week. Why study Biology? Relation to human health, hygiene. Relations existing between plants and animals. Relation of bacteria to man. Uses of plants and animals. Conservation of plants and animals. Relation to life of citizen in this city. Needs of plants and animals: (1) food, (2) water, (3) air, (4) proper temperature. Study of a single plant or animal in relation to its environment. Problems of city government: (a) storage, preservation and distribution of foods, (b) water supply, (c) overcrowded tenements, (d) street cleaning, (e) clean schools. Biological problems in city government.
Second week. Interrelations between Plants and Animals. Plants furnish food, clothing, shelter, and medicine. Animals use food, shelter. Man's use of plants as above. Man's use of animals as above. Plant and animal industries. Use of balanced aquarium as illustrative material.
Third week. Destruction of Food and Other Things by Mold. Home experiment. Conditions favorable to growth of mold. Food, moisture, temperature. Destruction of commodities by mold: food, leather, clothing.
Fourth week, fifth week. Destruction of Foods by Bacteria. Experiment. To show where bacteria are found. Soil, dust, water, milk, hands, mouth. Use and harm of decay. Relation to agriculture. Experiment. Conditions favorable and unfavorable to growth of bacteria: boiling, cold, sugar, salt. Bacteria in relation to disease briefly mentioned. Bacteria in industries.
Sixth week. Use of Stored Food by Young Green Plant: (a) for energy, (b) for construction of tissue. Experiment. Structure of bean seed. Draw to show outer coat, cotyledon, hypocotyl, and plumule. Test for starch and sugar (grape). Test for oil, protein, water, mineral matter. Use of all nutrients to seedling.
Seventh week. Other Needs of Young Plants. Home experiments to show (a) temperature, (b) amount of water most favorable to germination. Experiment. To show need of oxygen. To show that germinating seeds give off carbon dioxide. Proof of presence of carbon dioxide in breath. The needs of a young plant compared with those of a boy or girl.
Eighth week. Digestion in Seedling. Structure of corn grain. Experiment. To show that starch is digested in a growing seedling (corn). Experiment. To show that diastase digests starch. Discussion of experiments.
Ninth week. What Plants take from the Soil and How they do This. Use of roots. Proof that it holds plant in position, takes in water and mineral matter, and in some cases stores food. Influence of gravity and water. Labeled drawing of root hair. Root hair as a cell emphasized. Osmosis demonstrated.
Tenth week. Composition of the Soil. Demonstration of presence of mineral and organic substances in the soil. What root hairs take from the soil. Mineral matter necessary and why. Importance and sources of nitrogen. Soil exhaustion and its prevention. Nitrogen-fixing bacteria. Review bacteria of decay. Rotation of crops.
Eleventh week. Upward Course of Materials in the Stem. Demonstration of pea seedlings with eosin to show above. Demonstration of evaporation of water from a leaf. Action of stomata in control of transpiration. Cellular structure of leaf. Demonstration of elodea to show cell.
Twelfth week. Sun a Source of Energy. Heliotropism. Demonstration. Necessity of sunlight for starch manufacture. Necessity of air for starch manufacture. By-products in starch making. Oil manufacture in leaf. Protein manufacture in plant. Respiration.
Thirteenth week. Reproduction. Necessity for (a) perpetuation, (b) regeneration. Study of a typical flower to show sepals, petals, stamens, pistil. Functions of each part. Cross and longitudinal sections of ovary shown and drawn. Emphasis on essential organs. Pollination, self and cross. (Note. At least one field trip must be planned for the month of May. This trip will take up the following topics: The relations between flowers and insects. The food and shelter relation between plants and animals. Recognition of 5 to 10 common trees. Need of conservation of forests. An extra trip could well be taken to give child a little knowledge and love for spring flowers and awakening nature.)
Fourteenth week. Study of the Bee Or Butterfly with Reference to Adaptations for Insect Pollination. Study of an irregular flower to show adaptations for insect visitors. Fertilization begun. Growth of pollen tubes.
Fifteenth week. Fertilization Completed. Use of chart to show part played by egg and sperm cell. Ultimate result the formation of embryo and its growth under favorable conditions into young plant. Relation of flower and fruit, pea, or bean used for this purpose. Development of fleshy fruit. Apple used for this purpose.
Sixteenth week. Maturing of Parts and Storing of Food in Seed and Fruit. The devices for scattering the seeds and relation to future plants. Résumé of processes of nutrition to show how materials found in fruit and seed are obtained by the plant.
Seventeenth week. Plant Breeding. Factors: (a) selective planting, (b) cross-pollination, (c) hybridizing. Heredity and variation begun. Darwin and Burbank mentioned.
Eighteenth and nineteenth weeks. The Natural Resources of Man: Soil, Water, Plants, Animals. The relation of plant life to the above factors of the environment. The relation of insects to plants (forage and other crops) and the relation of birds to insects. Need for conservation of the helpful factors in the environment of plants. Attention called to some native birds as insect and wood destroyers.
Twentieth week. Review and Examinations.
Second Term
First week. The Balanced Aquarium. Study of conditions producing this. The rôle of green plants, the rôle of animals. What causes the balance. How the balance may be upset. The nitrogen cycle. What it means in the world outside the aquarium. Symbiosis as opposed to parasitism. Examples.
Second week. Study of the Paramœcium. Study of a hay infusion to show how environment reacts upon animals. Relation to environment. Study of cell under microscope to show reactions. Structure of cell. Response to stimuli, function of cilia, gullet, nucleus, contractile vacuoles, food vacuoles, asexual reproduction. Drawings to show how locomotion is performed, general structure. Copy chart for fine structure.
Third week. A Bird's-eye View of the Animal Kingdom. One day. Development of a multicellular organism. (Use models.) One day. Physiological division of labor. Tissues, organs. Functions common to all animals. Illustrative material. Optional trip to museum for use of illustrative material to illustrate the principal characteristics of (a) a simple metazoan, sponge, or hydrazoan, (b) a segmented worm, (c) a crustacean (Decapod), (d) an insect, (e) a mollusk and echinoderm, (f) vertebrates. (Differences between vertebrates and invertebrates.) The characteristics of the vertebrates. Distinguish between fishes, amphibia, reptiles, birds, mammals. Two days for discussion. Man's place in the animal series, elementary discussion of what evolution means.
Fourth week. The Economic Importance of Animals. Uses of animals: (1) As food. Directly: fish, shellfish, birds, domesticated mammals. (2) Indirectly as food: protozoa, crustacea. (3) They destroy harmful animals and plants. Snakes—birds; birds—insects; birds—weed seeds; herbivorous animals—weeds. (4) Furnish clothing, etc. Pearl buttons, etc. (5) Animal industries, silkworm culture, etc. (6) Domesticated animals.
Animals do harm: (1) To gardens. (2) To crops. (3) To stored food; examples, rats, insects, etc. (4) To forest and shade trees. (5) To human life. Disease: parasitism and its results,—examples, from worms, etc.; disease carriers fly, etc. Preventive measures. Methods of extermination.
References to Toothaker's Commercial Raw Materials. Use one day for laboratory work from references.
Fifth week. The Study of a Water-breathing Vertebrate. Two days. The fish, adaptations in body, fins, for food getting, for breathing. Structure of gills shown. Laboratory demonstration to show how water gets to the gills. Drawings. Outline of fish, gills. Required trip to aquarium. Object, to see fish in environment. One day. Home work at market. Why are some fish more expensive than others. Economic importance of fish. Relation of habits of (a) food getting, (b) spawning to catching and extermination of fish. Two days. Means of preventing overfishing, stocking, fishing laws, artificial fertilization of eggs, methods. Development of fish egg. Comparison with that of frog and bird.
Sixth week. The Factors Underlying Plant and Animal Breeding. Study of pupils in class to show heredity and variation. Conclusion. Animals tend to vary and to be like their ancestors. Heredity, rôle of sex cells, chromosomes. Principles of plant breeding. Selective planting, hybridizing, work of Darwin, Mendel, De Vries, and Burbank. Methods and results. Animal breeding, examples given, results. Improvement of man: (1) by control of environment, (a) example of clean-up campaign, 1913; (2) by control of individual, personal hygiene, and control of heredity. Eugenics. Examples from Davenport, Goddard, etc.
Seventh week. The Human Machine. Skin, bones and muscles, function of each. Examples and demonstration with skeleton. Organs of body cavity; show manikin. Work done by cells in body.
Eighth week. Study of Foods to determine: (a) nutritive value. Exercise with food charts to determine foods rich in water, starch, sugar, fats, proteins, mineral salts, refuse. One day. (b) Nutritive value of foods as related to work, age, sex, environment, cost, and digestibility. Foods compared to determine what is really a cheap food.
Ninth week. How the Fuel Value of Food has been Determined. The dietaries of Atwater, Chittenden, and Voit. The 100-calorie portion table and its use.
Tenth week. The Application of the 100-calorie Portion to the Making of the Daily Dietaries. Luncheon dietaries. A balanced dietary for pupil for one day. Family dietaries. Relation to cost. Reasons for this.
Eleventh week. Food Adulterations. Tests. Drugs and the alcohol question.
Twelfth week. Digestion. The alimentary canal of frog and of man compared. Drawings. (One day.) The work of glands. Work of salivary gland. Enzymes, internal secretions. Experiments to show (a) digestion of starch by saliva, (b) digestion of proteins by gastric or pancreatic juice, (c) emulsification of fats in the presence of an alkaline medium. Functions of other digestive glands. Movements of stomach and intestine discussed and explained.
Thirteenth week. Absorption. How it takes place, where it takes place. Passage of foods into blood, function of liver, glycogen.
Fourteenth week. The Blood and its Circulation. Composition and functions of plasma, red corpuscles, colorless corpuscles, blood plates, antibodies. The lymph and work of tissues. The blood and its method of distribution. Heart a force pump. Demonstration. Arteries, capillaries (demonstration), veins. Hygiene of exercise.
Fifteenth week. What Respiration does for the Body. The apparatus used. Changes of blood within lungs, changes of air within lungs. Demonstration. Cell respiration. The mechanics of respiration. Demonstration. Ventilation, need for, explain proper ventilation. Demonstration. Hygiene of fresh air and proper breathing. Dusting, sweeping, etc.
Sixteenth week. Excretion, Organs of. Skin and kidneys, regulation of body heat. Colds and fevers. Proper care of skin, hygiene. Summary of blood changes in body. Explanation of same.
Seventeenth week. Body Control and Habit Formation. Nervous system, nerve control. The neuron theory, brain psychology explained in brief. Habits and habit formation. Hygiene of sense organs.
Eighteenth and nineteenth weeks. Civic Hygiene and Sanitation. The Improvement Of One's Environment. Civic conditions discussed. Water, milk, food supplies. Relation to disease. How safeguarded. How help improve conditions in city.
Twentieth week. Review and Examinations.
(This outline may be introduced with Plant Biology, or, better, may come as application of the work in Second-term Biology.)
The Environment. Changes for betterment under control. How a city boy may improve his environment: by proper clothing, proper food and preparation of food, by care in home life; by sanitary conditions in neighborhood and in home.
Review of Activities of Cell. Irritability, food taking, assimilation, oxidation, excretion, reproduction. Similarity of functions of plant and animal cells. All cells perform these functions. Some cells perform functions especially well, e.g. contracting muscle cells. All cells need food and oxygen. Some must have this carried to them. A system of tubes carries blood which carries food and oxygen. Food must be prepared to get into the blood. Digestive system: mouth, teeth, stomach, intestines, glands, and digestive juices. Uses of above in preparing food to pass into the blood. Absorption of food into the blood. How oxygen gets to the cells. Nose, throat, windpipe, lungs; blood goes to lungs and carries away oxygen. Excretion. Cells give up wastes to blood and these wastes taken out of blood by kidneys and other glands and passed out of body. Sweat, urine, carbon dioxide.
Certain Kinds of Work performed by Certain Kinds of Cells. Advantage of this. Cells of movement. Muscles, tissues. Bones as levers necessary for some movements. This especially true for legs and arms. Skeleton also necessary for protection of internal organs and support of body. Making of special things in the body, e.g. digestive juices given to certain cells called gland cells. Working together or coördination of different organs provided for by nervous system. This is composed of cells which are highly irritable or sensitive. Collections of these nerve cells give us the power of feeling or sensation and of thinking.
Dietetics. Diet influenced by age, weight, occupation, temperature or climate, cheapness of food, digestibility.
Nutrients. List of nutrients found in seeds and fruits, also other common foods. Need of nutrients for human body. Nitrogenous foods, examples. A mixed diet best.
Digestion and Indigestion. What is digestion? Where does it take place? Causes of indigestion. Eating too rapidly and not chewing food. Eating foods hard to digest. Overeating. Eating between meals. Hard exercise immediately before or after eating.
Constipation. A condition in which the bowels do not move at least once every day. Dangers of constipation. Poisonous materials may be absorbed, causing lack of inclination to work, headache. Importance of regular habits of emptying the bowels. Each one must try to get at the cause of constipation in his own case. Causes of constipation. Lack of exercise, improper food, not drinking enough water, lack of laxative food, as fruits; lack of sleep, lack of regular habits. Remedies. Avoid use of drugs. Half hour before breakfast a glass of hot water, exercise of abdominal muscles, laxative foods, form habit of moving bowels after breakfast.
Hygiene of Circulation and Absorption. How digested foods get to the cells. Absorption. Definition. The passing of the digested food into the blood. How accomplished. Blood vessels. In walls of stomach and food tube. Membrane of cells separating food from blood. Food passes by osmosis through the membrane and by osmosis through the thin walls of the blood vessels.
Circulation of Foods. Blood contains foods, oxygen, and waste materials. Heart pumps the blood, blood vessels subdivide until very small and thin, so food, etc., passes from them to cells. Hygiene of the heart.
Transpiration and Excretion. Skin, function in excretion. Bathing. Care of skin. Hot baths. Bathe at least twice a week. Cold baths, how taken. Bathtub not a necessity. Effect of latter on educating skin to react. Relation to catching cold.
Care of Scalp and Nails. Scalp should be washed weekly. If dandruff present, wash often enough to keep clean. Baldness often results from dandruff. Finger nails cut even with end of fingers and cleaned daily with scrub brush.
Hygiene of Respiration. Definition of respiration. Object of respiration. (Connection between circulation and respiration.) Necessity of oxygen. Organs of respiration. Lungs most important. Deep breath, function. Ventilation, reasons for. Mouth breathing. Results. Lessened mental power, nasal catarrh, colds easily caught.
Plants Harmful To Man. Poison ivy and mushrooms. Treatment. Poisoning. Send for physician. Cause vomiting by (1) finger, (2) mustard and water. (Note. An unconscious person should not be given anything by the mouth unless he can swallow.) Relation of yeasts and bacteria to man. Fermentation a cause of indigestion. Relation to candy, sirups, sour stomach, formation of gas causes pain.
Bacteria of Mouth and Alimentary Canal. Entrance of bacteria by mouth and nose. Nose: "cold in the head," grippe, catarrh. Mouth: decay of teeth, tonsillitis, diphtheria. Germs pass from one person to another, no one originates germs in himself. Precautions against receiving and transferring germs. Common drinking cups, towels, coins, lead pencils, moistening fingers to turn pages in book or to count roll of bills. Tuberculosis germs. Entrance by mouth, lungs favorite place, may be any part of body. Dust of air, sweeping streets, watering a necessity. Spitting in streets and in public buildings. Germs of typhoid fever. Entrance: water, milk, fresh uncooked vegetables, oysters. Thrive in small intestines. Preventable. Typhoid epidemics, methods of prevention of typhoid. Conditions favorable for growth of specific disease germs. Work of Boards of Health.
Home sanitary conditions, sunlight, air, curtains and blinds, open windows. Live out of doors as much as possible. Cleanliness. Bare walls well scrubbed better than carpets and rugs. Lace curtains, iron bedsteads, one thickness of paper on walls. Open plumbing, dry cellars, all garbage promptly removed.
This outline is largely the work of Dr. L. J. Mason and Dr. C. H. Morse of the department of biology of the De Witt Clinton High School.
WEIGHTS, MEASURES, AND TEMPERATURES
As the metric system of weights and measures and the Centigrade measurement of temperatures are employed in scientific work, the following tables showing the English equivalents of those in most frequent use are given for the convenience of those not already familiar with these standards. The values given are approximate only, but will answer for all practical purposes.
| Weight | ||
|---|---|---|
| Kilogram | kg. | 2-1/5 pounds |
| Gram | gm. | 15-½ grains avoirdupois. 1/28 of an ounce avoirdupois. |
| Capacity | ||
| Liter | l. | 61 cubic inches, or a little more than 1 quart, U. S. measure. |
| Cubic centimeter |
cc. | 1/16 of a cubic inch. |
| Measures of Length | ||
| Metric | English Equivalents | |
| Kilometer | km. | 2/3 of a mile. |
| Meter | m. | 39 inches. |
| Decimeter | dm. | 4 inches. |
| Centimeter | cm. | 2/5 of an inch. |
| Millimeter | mm. | 1/25 of an inch. |
The next table gives the Fahrenheit equivalent for every tenth degree Centigrade from absolute zero to the boiling point of water. To find the corresponding F. for any degree C., multiply the given C. temperature by nine, divide by five, and add thirty-two. Conversely, to change F. to C. equivalent, subtract thirty-two, multiply by five, and divide by nine.
| Cent. | Fahr. |
|---|---|
| 100 | 212 |
| 90 | 194 |
| 80 | 176 |
| 70 | 158 |
| 60 | 140 |
| 50 | 122 |
| 40 | 104 |
| 30 | 86 |
| 20 | 68 |
| 10 | 50 |
| 0 | 32 |
| -10 | 14 |
| -20 | -4 |
| -30 | -22 |
| -40 | -40 |
| -50 | -58 |
| -100 | -148 |
| Absolute zero | |
| -273 | -459 |
The following articles comprise a simple equipment for a laboratory class of ten. The equipment for larger classes is proportionately less in price. The following articles may be obtained from any reliable dealer in laboratory supplies, such as the Bausch and Lomb Optical Company of Rochester, N.Y., or the Kny-Scheerer Company, 404, 410 West 27th Street, New York City:—
| 1 | balance, Harvard trip style, with weights on carrier. |
| 1 | bell jar, about 365 mm. high by 165 mm. in diameter. |
| 10 | wide mouth (salt mouth) bottles, with corks to fit. |
| 10 | 25 c.c. dropping bottles for iodine, etc. |
| 25 | 250 c.c. glass-stoppered bottles for stock solutions. |
| 100 | test tubes, assorted sizes, principally 6" × ¾". |
| 50 | test tubes on base (excellent for demonstrations). |
| 2 | graduated cylinders, one to 100 c.c., one to 500 c.c. |
| 1 | package filter paper 300 mm. in diameter. |
| 10 | flasks, Erlenmeyer form, 500 c.c. capacity. |
| 2 | glass funnels, one 50, one 150 mm. in diameter. |
| 30 | Petri dishes, 100 mm. in diameter, 10 mm. in depth. |
| 10 | feet glass tubing, soft, sizes 2, 3, 4, 5, 6, assorted. |
| 1 | aquarium jar, 10 liters capacity. |
| 2 | specimen jars, glass tops, of about 1 liter capacity. |
| 10 | hand magnifiers, vulcanite or tripod form. |
| 2 | compound demonstration microscopes or 1 more expensive compound microscope. |
| 300 | insect pins, Klaeger, 3 sizes assorted. |
| 10 | feet rubber tubing to fit glass tubing, size 3/8 inch. |
| 1 | chemical thermometer graduated to 100° C. |
| 15 | agate ware or tin trays about 350 mm. long by 100 wide. |
| 1 | gal. 95 per cent alcohol. (Do not use denatured alcohol.) |
| 1 | set gram weights, 1 mg. to 100 g. |
| 1 | razor, for cutting sections. |
| 1 | box rubber bands, assorted sizes. |
| 1 | support stand with rings. |
| 2 | books test paper, red and blue. |
| 10 | Syracuse watch glasses. |
| 1 | steam sterilizer (tin will do). |
| 1 | spool fine copper wire. |
| 1 | test tube rack. |
| 5 | test tube brushes. |
| 10 | pairs scissors. |
| 10 | pairs forceps. |
| 20 | needles in handles. |
| 10 | scalpels.[TN8] |
| 12 | mason jars, pints. |
| 12 | mason jars, quarts. |
| 1 | alcohol lamp. |
| 1 | gross slides. |
| 100 | cover slips No. 2. |
| 1 | mortar and pestle. |
| 2 | bulb pipettes. |
| 1 | liter formol. |
| 1 | oz. iodine cryst. |
| 1 | oz. potassium iodide. |
| 6 | oz. nitric acid. |
| 6 | oz. ammonium hydrate. |
| 6 | oz. benzole or xylol. |
| 6 | oz. chloroform. |
| ½ | lb. copper sulphate. |
| ½ | lb. sodium hydroxide. |
| ½ | lb. rochelle salts. |
| 6 | oz. glycerine. |
The materials for Pasteur's solution and[TN9] Sach's nutrient solution can best be obtained from a druggist at the time needed and in very small and accurately measured quantities.
The agar or gelatine cultures in Petri dishes may be obtained from the local Board of Health or from any good druggist. These cultures are not difficult to make, but take a number of hours' consecutive work, often difficult for the average teacher to obtain. Full directions how to prepare these cultures will be found in Hunter's Laboratory Problems in Civic Biology.