Heroes of science

Zoology does for animals what botany does for plants. It is the science which treats of the resemblances and differences of animals, their shapes, and habits, and which explains their position on the earth in different countries, and classifies them. It is inseparably linked on to the study of comparative anatomy and to physiology which treats of the internal structures and the influence which the outside world has upon the living thing. Like botany, the science arose in a simple manner, and men first of all learned to distinguish one animal from another, giving them names. Then their habits were noticed, and some attempt was made to arrange animals by their greater or less resemblances of external shape. The age of the wonderful affected zoology as it did botany, and the intellectual darkness of the Middle Ages prevented progress. The writings of travellers, the discovery of the microscope, and civil and religious liberty, caused the rise of zoology, and the classifications gradually began to include the past or extinct kinds of animals with those which are now existing in a great scheme, which indicates the succession of living things upon the earth.

As a great branch of natural history, it was to be expected that zoology would be studied with botany; and in fact, nearly all the great botanists have been able zoologists, whilst nearly every great zoologist began with botany.

Aristoteles was as great a hero in zoology as he was in botany, and he may be said to have founded the science. Certainly, some of the principal divisions of the animal kingdom were taught by him. He was the first to make an attempt to explain the anatomy of animals, the functions or duties of different parts of their bodies, and to compare them with those of man. He discussed their resemblances and differences with great acuteness. He was especially distinguished as a student of fishes, making a vast number of observations of his own, and collecting those of other writers. After much consideration, Aristoteles wrote upon the distinction between living things and inanimate nature, and we owe him the notion of the distinctions between the genus and the species. He wrote with regard to the species: “An animal species is an assemblage of individual animals, in which not only the whole form of any one resembles the whole form of any other, but each part in any one resembles the corresponding part in any other. Thus, every horse not only resembles every ether horse generally, but the eye or the hoof of every horse resembles the eye or hoof of every other horse. They are, therefore, the same in the character of the individual parts.” “A genus is an assemblage of individuals in which any one bears, upon the whole, an obviously perceptible resemblance to any other. But the corresponding portion in the different species of the same genus, usually differ in colour, form, numbers, size, and proportion.” This is not so clear as the notion of the species, and he extended the term genus to what is now called an assemblage of genera, that is to say, a family, order, or class. He clearly distinguished between white-blooded and red-blooded animals, and was aware of the mysterious connection between the existence of a spinal column, made up of bones, or vertebræ, and red blood. He makes vertebrated, or backboned, animals to take the first place in his scale of classification. Classifying man, viviparous and oviparous quadrupeds, birds, fishes, cetaceous animals (whales), and serpents amongst the red-blooded, Aristoteles put down as white, or no blooded animals, insects, or creatures divided into segments, cuttlefish, with soft substance, rather soft-shelled animals, like lobsters, and hard-shelled creatures such as oysters. He examined, one by one, all the species he could procure, and then classed together as a subordinate generic group all those, which resembling each other in the more important parts of their structure, differed only in size or colour, or in other points of little importance.

Aristoteles founded the natural history of his age, and no one came near to him. He left nobody behind to follow his work.

In after years, Plinius wrote on beasts, fishes, birds, and insects, and on human and comparative anatomy, but he made no great advance on Aristoteles. Then there occurred as great a gap in the study of zoology as happened in botany, and many hundreds of years elapsed before progress was made.

Conrad Gesner, a Swiss, made the first great step in zoology after the ancients, and his life was a most remarkable one. A writer says of him, that he was a shining example of the truth of the remark, that those who have most to do, and are willing to work, find the most time. He was a great scholar, and a profound naturalist. He began life in extreme poverty, soon became an orphan, laboured whilst ill, and sacrificed himself for the sake of others. A son of a poor skinner and worker of hides, he was born in 1516, at Zurich, and had to suffer pinching poverty, with his numerous brothers and sisters. An uncle was kind to the boy, and began to educate him, but death stepped in and he lost his kind relation. When only thirteen years of age, Gesner was cast upon the world, his father having died fighting in the battle of Zug. The lad was seriously ill and dropsical, and his sole fortune was a little knowledge of classics, which he had picked up. Probably one of the professors at Zurich, Ammian by name, and who had instructed him, gave him introductions, for we find the lad at Strasbourg when fifteen years of age. His thoughts were to go into the Lutheran Church, and it is certain that the Lutheran Wolfgang Fabricius Capito gave him some employment, and enabled him to begin the study of Hebrew. Returning again to Zurich, the university there gave him a little pension, to enable him to travel, and he went into France to Bourges. There he taught at a school, and occupied his spare time in learning Greek and Latin. Then he went to Strasbourg again, hoping for employment, and finding none, was asked to return to Zurich, and to teach in the university. At the age of twenty he married, and, of course, much against the wishes of his friends, who do not appear to have done anything for him, except to have given gratuitous advice. Although the Church was to be the career of Gesner, he took much interest in the healing art, and resigning his position at Zurich, he went, having a small pension, to Basle as a medical student. Anxious to know the wisdom of the Greek physicians, he paid unusual attention to that language, and edited an edition of a dictionary of it. This study brought strange results, for he was offered a professorship of Greek at Lausanne, and he accepted the position. He was very young, and yet learned men found his friendship valuable. Going, subsequently, to Montpellier, he became acquainted with a naturalist named Rondelet, and he gradually began to earn enough money to be independent. So he returned to Basle, and in 1541, being twenty-five years old, took his degree in medicine. He settled in practice at Zurich, and occupied his spare time in studying zoology and botany, and soon became wealthy. Occasionally he travelled, and during one of these trips he became acquainted with the leading men at Venice and Augsburg, and at their instance began a great work, a kind of universal catalogue of Greek, Hebrew, and Latin works. All this time he was slowly and surely studying animals and plants, and in 1551 the first part of his “History of Animals” appeared, to be followed by others in 1554, 1555, and 1556. The volumes contained descriptions of viviparous quadrupeds, that is to say, four-footed beasts, whose young are born in active movement; of oviparous quadrupeds, or those which lay eggs; of birds and of fishes, and other aquatic animals. He wrote also upon insects. All agree that this book is a miracle of industry, having for its object no less than a general history of animated nature. It contains a careful criticism of the works of previous authors, and, besides much valuable and solid knowledge on zoology, many interesting remarks on the habits and medicinal uses of animals. He followed the method of Aristoteles, and the notion of the genus was, of course, not satisfactorily established; but the book was the source of much of modern zoology, from which succeeding writers drew largely.

Gesner’s botanical works were as great as those relating to animals, and he designed and painted fifteen hundred figures of plants, which were of great use to his successors. As if he had not enough to do, he translated the Greek works of Aelian, on animals, in 1556. Scientific and industrious, he had much to contend with, and was short-sighted. He was the first person who used concaved glasses to remedy this defect in his sight. As years rolled on, Gesner was much liked and honoured in his native town; he was very amiable, a great peacemaker, and a liberal citizen. He established a botanic garden, and gave employment to artists. Whilst in the full vigour of life, and in active practice as a physician, the plague attacked Zurich, and Gesner successfully combated the contagious disorder in many cases. He exposed himself without fear, after the fashion of most medical men, and unfortunately caught the disease. When the worst symptoms came, he knew his hour was at hand, and asked to be carried into his library and museum, where all the treasures he had collected and described, to the delight of his students and friends, were deposited. There he breathed his last, in the arms of his affectionate wife, for whose love contagion had no terrors. He died with the calmness of a Christian philosopher, on the fifth day of his attack, at the early age of forty-nine. His remains rest, much honoured, in the cloister of the Greek church at Zurich. Not only did Gesner consolidate the knowledge of the animal and vegetable kingdom of his day, but he also influenced other authors to do good work, and to avoid unkind criticism. His calm, candid, and equable temper enabled him to soothe the angry feelings of others, under their real and imaginary wrongs. He laid aside his own labour to assist others, and he devoted much time to the supervision and publication of a work which was left incomplete, by a deceased friend, so as to provide for the family.

Gesner’s life is a very good proof that where there is a will there is a way, and that poverty does not impede the path of a thoroughly industrious and earnest man. The poor skinner’s son’s name is respected at the present day, and will be so, as long as science lasts.

The interesting life of Ray has already been given amongst those of the heroes of botany; he was, however, a zoologist of the first class, and his devotion to that part of natural history was part of his great friendship for Mr. Willughby. This promising young man studied under Ray, at Cambridge, and whilst the master took plants under his care and study, the pupil began to work at animals. They made a tour together, visiting France, Spain, Italy, Germany, and the Low Countries. Ichthyology, or the study of fishes, and ornithology, or the study of birds, occupied the attention of Willughby. Having collected a vast number of specimens and observations, they returned to England, and Willughby immediately commenced working with a view to the publication of a great work on the animal kingdom. He even contemplated a visit to America; but health failed, and he died in the prime of life, on July 3rd, 1672. The education of his two infant sons was confided to Mr. Ray, who was one of his executors. Willughby thought his works too imperfect for publication, but Ray felt otherwise, and urged it upon him for three reasons: first, the glory of God; secondly, the assistance of others in the same studies; thirdly, the honour of his native land. Upon these grounds he gave his consent, and Ray became their editor. A book on birds, “The Ornithologia,” was the result, and it contains a large amount of original observation, and is a full and exact description of the habits and maladies of birds, and the best means of domesticating them. Excellent anatomical descriptions are added. Subsequently, a book on the fishes of the Mediterranean appeared.

The merits of Willughby as a natural historian still continue to be recognized. He was a most accomplished zoologist, and he gave Ray and Linnæus the method of classification of animals which is usually associated with their names. Ray acknowledged this, and he says that he found among his friend’s manuscripts the histories of beasts and insects, no less than of birds and fishes, “digested with a method of his own.” He was not a simple wealthy and intelligent amateur, for he was master to one of the greatest naturalists. Ray, in editing Willughby’s “Book on Birds,” gives a most touching preface to the memory of his friend. He says, “He was from childhood addicted to study, and ever since he came to the use of reason, so great a husbander of his time, as not willingly to lose, or let slip unoccupied, the least fragment of it; detesting no vice more than idleness, which he looked on as the parent and source of all others. Of his skill in natural philosophy, chiefly the history of animals, I shall say no more at present, but that it hath not yet been my hap to meet with any man, whether in England or beyond seas, of so general and comprehensive knowledge therein.”

A very different career, but one which has had a greater general influence on natural history, was that of John Swammerdam, who was born at Amsterdam, in 1637, his father being an apothecary. His grandfather, Jacob Dirkz, was born in the village of Swammerdam, near Leyden, and his father, a well-to-do apothecary, lived there and took his name from the village. He married Berendina Corvera and settled at Amsterdam. The family lived in comfort, and the little one was destined, like many other naturalists, to the Church. His education consisted of sound Latin and Greek, and when he became old enough, he began to feel that there were responsibilities about his future office as a clergyman, which he did not think he could fulfil. Holland at that time was in a religious ferment, and sects of all kinds existed, religion being more talked about than practised. The lad, as he grew up, desired to follow in his father’s footsteps, and to learn the healing art; but his genius led him to the study of nature. Before he was fifteen years of age, he began to make collections of natural history objects, and whenever he could get away from home, and spare time from his medical studies, he pursued his favourite employment, searching the woods and fields, the sand-hills and muddy shores, the lakes, rivers, and canals, for insects, worms, and molluscs, until he acquired, even as a youth, a more extensive knowledge of the lower animals than all the naturalists who had preceded him. In 1661 he went to Leyden and studied surgery and anatomy. In this last he excelled, and became celebrated for his methods of preserving dissections. Then he went to Saumur, in France, and to Paris, where he gained the friendship of Thévenot the traveller, who was his patron subsequently, and assisted him when in Amsterdam in after years, by obtaining permission for him to dissect human bodies. His fellow-pupil was Nicholas Steno, of whom more will be said under the title of “Heroes of Geology.” On his return to Leyden, Swammerdam discovered the method of injecting arteries with coloured wax, and of keeping the internal organs in a dry condition for purposes of study, and investigated the nature of the lymphatics. He graduated soon after, and after receiving his diploma, returned to his old love, nature, and occupied nearly all his time in the anatomy and physiology of insects.

Swammerdam worked so incessantly, that he got into bad health, and was obliged to relinquish the medical profession for a time. He followed up his researches into the minute construction of insects, and really never ceased them until death. The Grand Duke of Tuscany visited Amsterdam at this time, and examined Swammerdam’s collections. Greatly impressed with their value, and with the splendid dissections, he offered a home to the young naturalist in his palace, and twelve thousand florins for the collection. Swammerdam, however, did not care to wear a collar; and loving freedom of thought, which he did not think he would have in Italy, declined the offer. He knew that he would be expected to change his religious tenets, and said that he would not sell his soul for money. He published a “General History of Insects,” in 1669, and soon afterwards broke down, entirely, in health, so that he had to go into the country to rest and do nothing. But this was impossible; and he began to study bees, and their natural history. Probably it was this constant weak health, and the solitude necessary for the peculiar nature of his work and observations, that had a very remarkable influence on the mind and emotions of this great investigator. Always religious, he longed more and more for communion with his Maker and the author of all the wonders he was constantly studying. When in better health he was happy in his thoughts, and considered that it was his duty to study nature; but when ill, from the effects of overwork, he began to think that his labours were leading him astray, and that to seek the good opinion of his fellow-creatures and to become famous, was a sin. Sometimes he gave up science, to begin again with fresh zeal, and then he would neglect it, giving up his whole time to religion. Unfortunately he was unreasonable in his method of working. Boerhaave, the great physician, thus wrote of Swammerdam: “He laboured so assiduously at this work as to destroy his constitution, nor did he ever recover a shadow of his former strength. The labour, in fact, was beyond the power of ordinary men—all day he was employed in examining objects, and at night described and delineated what he had seen by day. At six in the morning, in summer, he began to receive sufficient light from the sun to enable him to trace the objects of his examination. He continued dissecting until twelve, with his hat removed lest it should impede the light, and in the full blaze of the sun, the heat of which caused his head to be constantly covered with profuse perspiration. His eyes being constantly exposed to a strong light, the effect of which was increased by the microscope, they were so affected by it, that after midday he could no longer trace the minute bodies which he examined, although he had then as bright a light as in the forenoon.”

Swammerdam investigated the nature of the changes of outside form and internal structure which accompany insect life. Some of his drawings of the escape of the ephemera fly from its sheath of delicate skin on the surface of the water, and out of the wingless or nymph condition, are very beautiful. But his accuracy regarding the minute internal changes of the tissues and organs in the larva, pupa, and perfect insect is being more and more acknowledged. He taught that these changes were not sudden, but that a continuous growth of organs and tissues culminated at certain times of the life of the insect. The larva, or caterpillar, admirably adapted for its course of life, was a stage of the life cycle of a more perfect form, the imago or flying insect. Swammerdam stated that all the organs of the perfect insect—a butterfly, for instance—were in a visible yet only slightly developed condition in the caterpillar. And late researches are leading to prove that he was right, for the wings of the future fly are to be detected in the body of the tiny crawling thing that escapes from the egg.

Happy in this toil when he was well, for it was all about what was entirely new and previously unknown, he often laboured on, when he was ill, with “sighs and tears.” Naturally sensitive, pious, and very amiable, he at one time quite gave up his work under the influence of a remarkable woman, Antoinette Bourignon. She was a wealthy, well-educated person, extremely plain, and who believed that a mission had been given her to preach according to her own fancies, and not in accordance with the general doctrines of the age. She seems to have stimulated Swammerdam to lead a purely religious life, and to give up his studies. It was the age of sects and of intolerance; and possibly the disagreeable reception which this certainly very good woman met with, made the man care more about her peculiar tenets. He began, seriously, to try and sell his collections, made catalogues of his possessions, and corresponded with Antoinette. While various negotiations were pending, Swammerdam published the results of his ten years’ labour and the “Anatomy of the Day Fly,” a great work, and his best. Then he went on a journey into Denmark to use his influence with the king in order to get Antoinette a home in that kingdom, the Lutherans of Holland having ordered her to leave their country. He was not successful; and probably this affair made a great commotion at home. On Swammerdam’s return, his father, enraged at him for his utter carelessness about earning money and his want of application to business, determined to allow him only a small sum of money to live upon. He was in utter despair, for this prevented his following his wish to lead, for the future, a life of meditation and religion. The father died soon afterwards, and a lawsuit was commenced by the family to prevent Swammerdam having his share of the property. This trouble brought on illness, and severe ague followed, and, although recovery took place, the sensitive, able man sank soon afterwards. Swammerdam made an epoch in zoology by showing the value of the microscope, and by his extreme exactitude in descriptions, drawings, and dissections. His contributions to human anatomy alone will always render his name illustrious.

Although everybody must regret that Swammerdam had not good means, and that his work was so sadly brought to a close by poverty and trouble, yet it must be remembered that wealth is not a great incentive to distinction in subjects that require great self-denial, and which are not much valued by what is called public opinion. The temptations incident to, and the real duties of wealth, are as great antagonists of successful scientific research, as poverty. And certainly the frivolity and vice of the wealthier classes of Europe, during the earlier part of the eighteenth century, were not likely to inspire any of their members with a desire for natural science. But some very remarkable instances occurred, in which the genius and determination of some great men prevailed over the intolerance and habits of the age, and enabled them to become men of great mark in zoology and other subjects.

The first to be noticed is René Antoine Ferchault de Réaumur, who was born at Rochelle, in western France, in 1683. Well born, and having wealthy parents, he was well educated, and destined for the law. He did not follow the propensities of the age, but began to study the arts and manufactures of France with great care, and to spend his spare time in natural history researches. From what is known of his career, it is very evident that he had learned chemistry and mineralogy, and that his education had been a most careful and liberal one. His fortune was considerable, and it not being necessary for him to work for his bread, he determined to follow the bent of his inclinations. When twenty years of age, Réaumur went to Paris, and his first essay was in the form of some geometrical work which was read before the Academy of Sciences. At the early age of twenty-four he was admitted a member of that learned and somewhat emotional body, and was a very constant contributor to its publications for fifty years. At first his desire was to improve the arts and manufactures of his native land, and in 1711 he made experiments upon the manufacture of ropes, and he showed that the strength of a cord is less than the sum of the strength of the threads of which it consists, whence it follows that the less a rope is twisted after a certain point, the stronger it is. In 1715 he began to study the process of colouring artificial pearls, and probably it was during these researches that his attention was attracted towards natural history. He found out the nature of the substance which gives the pearly lustre to fish scales, and then he investigated the growth of scales. Following up his subject, he examined into the method of growth of the shells of molluscs. In one of his journeys in Languedoc, he discovered some substances resembling turquoise in colour, and they were used as gems; but he pushed the matter further, and discovered a very remarkable fact. The extinct animal called mastodon, from the peculiar teat-shaped projections on its huge teeth, roamed over Europe in the last geological age, and its teeth, covered with a very strong enamel, have been preserved in strata, or in fissures. Under the influence of the chemical action going on in rocks, the enamel becomes occasionally coloured, so as to resemble a turquoise-coloured porcelain. This was evident to Réaumur, who wrote upon the fact. Other studies took him away from natural history for a while, but they certify to the energy and hard work of the man and his great accuracy. Réaumur’s experiments in the manufacture of iron and steel were of great importance, and it was an attempt to get the art of making steel introduced into France, that urged him on. He made good use of his knowledge, for on publishing his methods of work, the Regent gave him a pension of 12,000 livres a year. Next he discovered the art of tinning iron, and whilst experimenting, Réaumur first noticed that many metallic substances in passing from the heated fluid condition to the cold state, have a tendency to assume particular geometrical or crystalline forms. Among his useful discoveries were plans for the manufacture of porcelain, and they were of great use to France. A thermometer, with a scale of temperature, still largely used in some parts of the world, was invented by him, and he took the freezing and boiling points of water as fixed points, and divided the interval into eighty degrees. The present centigrade thermometer used in France is made on the same plan, but the interval is divided into one hundred degrees. Labouring as a physicist, still all this time Réaumur was doing wonderful work in zoology. He described the means by which many echinodermata—sea-urchins and sea-stars—execute their movements, and discovered the curious manner in which many crustacea, such as crabs and lobsters, throw off their limbs and repair them. But his real and lasting work was on insects, which occupied all his best and later years. Living in perfect quietude, without any great worries, sometimes at his estate at Saurlonge, and at other times at Bercy, near Paris, he worked on, giving all his energies to his subject. His labours, he stated, were published with a view to assist future investigators, and most of them were original. He kept up his pretty country house and garden, and observed the insects and their habits, and especially their methods of changing form. He followed Swammerdam in these investigations, and although there are some differences of opinion between the two great men, still they both made their mark in the investigation of that part of natural history which deals with the progressive development of the minute young to the full-grown creature. Réaumur was sufficiently wealthy to form a large collection of animals, and a very able man, M. Brisson, was employed by him as its curator, and was allowed to describe the quadrupeds and birds. Réaumur did not care so much about classifying insects, as describing their habits and anatomy; but his six great volumes are still most valuable memorials of his conscientious care. He says that the number of observations necessary for a tolerably complete history of so many minute animals is prodigious. When one reflects on all that an accomplished botanist ought to know, it is enough to frighten him. His memory is loaded with the names of twelve or thirteen thousand plants, and he is expected to recall, on occasion, the image of any one of them. There is perhaps not one of those plants but has insects peculiar to itself; and some trees, such as the oak, give sustenance to several hundred different species. And after all, how many are there that do not live on plants? How many species that devour others? How many that live at the expense of other animals? How many species are there, some of which pass the greater part of their time in water, while others pass it entirely there? The immensity of nature’s works is nowhere more apparent than in the prodigious multitudes of these little animals. This being the case, he deems it impossible for any one man to acquire a knowledge of all the insects of even a limited district; therefore, instead of burthening the memory with the characteristic distinctions of these creatures, to the neglect of matters of greater importance, he recommends attention to particular genera, and especially to those which are of most frequent occurrence, that a knowledge of their peculiarities, food, and propagation, and the different forms they assume, may be accurately obtained.

In the first two volumes, Réaumur treats of caterpillars, their changes of form into the chrysalis, and this into the butterfly; about their different kinds and habits, and concerning the other insects which attack them, and live within them, in their early stage.

The third volume includes the description of the habits of the clothes moths, and the plant-lice, or aphides; the fourth treats of gall insects and two-winged flies; the fifth contains the history of bees, and the sixth of wasps and hornets. The natural history of the grasshoppers, crickets, and beetles was to have been written in a seventh volume, but it was never completed. The published volumes contain much very valuable information, and their great merit consists in the wonderful care Réaumur took, in investigating facts and in recording them carefully and systematically. He especially studied the instincts of insects, and thus brought their nervous system into prominent notice, and also the evident connection between the surrounding conditions and the peculiar lives of animals.

Years rolled on and the worthy man became old, but still persisted in his simplicity of life and desire for study. He was so superior in intellect to the class to which he belonged, that he lived free from jealousy and intrigue. Probably few men have led a happier life than Réaumur, and certainly his useful works will last as long as mankind. At the age of seventy-four he met with an accident whilst riding, and died October 18th, 1757. He had no personal vanity, and, being influenced by the true scientific spirit, sought truth and not personal distinction and reward.

Linnæus, whose life has been given under the title of a hero in botanical science, was almost as great a zoologist as botanist and mineralogist. His classification of animals produced as great a change in the direction and possibility of studying zoology, as that of plants did in the case of botany. It led the way, through an artificial system, by which animals could be readily known, to a natural system which united animals not only by their common general shape, but also by the nature, position, and use of their internal organs. His system of naming animals was equal to that of plants, and the reasonable generic and the applicable specific names, going together, stamped the animal with a kind of individuality. Classification, description, and proper naming were the important parts of Linnæus’s zoology.