Dochmius duodenalis, Leuckart.—Much time might be occupied and wasted over the nomenclature of this parasite. In my previous treatise, and for reasons there stated, I placed it under the genus Sclerostoma. On rather slender grounds Dubini formed the genus Anchylostoma for its reception, but Von Siebold thought that, on account of the absence of symmetry in the arrangement of the so-called dental organs, Dubini’s genus might very well be allowed to remain. Bilharz, Diesing, Küchenmeister, Wucherer, and others have retained the genus as either Anchylostoma or Anchylostomum. Schneider keeps it amongst the Strongyli; but after all that has been said and written there can, I think, be no doubt that if Dujardin’s genus Dochmius is to be retained at all, Dubini’s worm must be placed in it. The comparisons instituted by Leuckart afford sufficient proof of the intimate alliance as between Anchylostoma and Dochmius. Professor Molin thought to meet the difficulty by calling the worm Dochmius anchylostomum, but the specific term, duodenale, should certainly be retained.

This worm was discovered by Dubini at Milan, and though at first thought rare, it is now known to be tolerably common throughout Northern Italy. The worm has also been recently found by Dr Kundrata at Vienna, in an Austrian subject. According to Pruner, Bilharz, and Griesinger, it is abundant in Egypt. Griesinger believed that about one fourth of the people of that country suffered from anæmic chlorosis, solely in consequence of the presence of this worm in the small intestines. From Wucherer’s observations especially, we know that Dubini’s worm is not limited to the localities above mentioned, for it occurs in the western tropics, in Brazil, and even in the Comoro Islands.

The worm may be described as a small nematode, the males measuring 3/8″ or rather more, whilst the females extend to very nearly 1/2″ (12 mm.). The head is pointed and tapering, and bent forward, having the mouth directed towards the ventral aspect. The oral opening is armed with four asymmetrically disposed, unequally-sized, horny, conical, converging teeth. The neck is continuous with the cylindrical body, which is 1/80″ in thickness. The body terminates in a straight cone-shaped, or rather sharply-pointed tail in the female, the caudal extremity of the male ending in a partially inflexed, blunt point. In the male there is a cup-shaped, bilobed bursa, the membranes of which are supported by eleven chitinous rays, ten being simple, whilst the median, or odd one, is bifurcated at the summit. The mode of reproduction is viviparous. Adult males and females occur in the proportion of one of the former to three of the latter.

As above mentioned, it was Griesinger who first pointed out the clinical importance of this entozoon. He first explained the manner in which the worm produces anæmia, the persons attacked losing blood as if they were being bitten by innumerable small leeches. Like the rest of their kindred, these worms are veritable blood-suckers. In the first instance the views of Griesinger met with opposition, but they have since received abundant confirmation. Whilst Küchenmeister’s ‘Manual’ furnishes an excellent account of the disorder as known in Europe, we are chiefly indebted to Wucherer for what is known of the disorder in Brazil. The experiences recorded in the ‘Deutsches Archiv für Klinische Medicin’ for Sept. 27th, 1872 (s. 379–400), were amongst the last that appeared from the pen of that gifted and amiable physician. As little or no notice of his writings appears to have been taken by professional men in this country, I depart somewhat from the design of this work when I venture to abstract a few of the clinical particulars which he has supplied. Their importance in relation to sanitary science is obvious, inasmuch as these parasites are introduced into the human body by drinking impure water, or, at least, water which either contains the free larvæ of the worm, or the intermediary bearers that harbor the larvæ.

It should be borne in mind that Dubini’s original discovery was made at Milan in 1838, whilst Griesinger’s recognition of the worm as a cause of the Egyptian chlorosis resulted from a post-mortem examination made on the 17th of April, 1851.

In the journal above mentioned, Wucherer records his own discoveries as follows (‘Ueber die Anchylostomunkrankheit,’ &c.):—“Although Griesinger with well-founded confidence gave an account of his ‘find’ and its significance, yet it remained for a long time unnoticed and unutilised, till at length a case led me to corroborate it. During my many years’ residence in Brazil, especially during the first year, I had very frequent opportunities for witnessing the tropical chlorosis, but seldom to treat it, as it is one of those diseases for which Brazilians seek no medical assistance. Its treatment falls to the lot of the curiosos, curadeiros (quacks), who employ the fresh pulp of a species of fig as a remedial agent with the best results. On the 13th of December, 1865, I was called to the Benedictine monastery in Bahia to see a slave of the order suffering from hypoæmia. The patient was about thirty years of age, married, a strongly built mulatto. He was a field laborer on the Ingua plantation of the order, who exhibited in a conspicuous degree all the symptoms that occur in hypoæmia except the diarrhœa. He was well nourished, but strikingly pale, his whole face, but especially the eyelids, being œdematously swollen, as also were the feet, legs, and hands. The hands and feet were very cold. His appearance betrayed the most horrible anguish or low despondency. With difficulty only could he raise himself, being obliged to lie down again immediately on account of his weakness. Auscultation revealed a diminished respiratory murmur, and bronchial expiration in both lungs. The pulse was very rapid and small, the patient complaining of pain in the region of the heart. He had frequent palpitation when he moved, and he complained of pain in other parts of the body. His abdomen was much distended by gases, but not sensitive to pressure from without, except in the region of the stomach. The urine was clear, its specific gravity 1007 to 10231/2°. Under great difficulties he resided for several months after his marriage at Inhatâ. Earlier he had been on the estates of the order at Rio de S. Francisco. He there suffered for a long time from intermittent fever, but at Inhatâ he entirely recovered. At Inhatâ the slaves frequently suffered from hypoæmia, but in S. Francisco not at all. He appears not to have made any misuse of brandy. The slaves of the order were well cared for, and supplied with good and wholesome nourishing food. The patient had already, for a long period, treated himself with steel wine, yet was continually getting worse and worse. He had not taken the pulp of the fig. As I was unaware he had suddenly become so ill, they hastily despatched a message to the town. There was no good to be expected from the further employment of iron, and the patient was in such a condition that from the very first I despaired of his recovery. I immediately prescribed the pulp of the Gammeleira (Ficus doliaria), but it could not be easily obtained. Considering that the Gammeleira would have a drastic effect, I therefore prescribed two grammes of elaterium, to be divided into eight doses, of which he should take one every three hours.” Dissatisfied with this advice, however, Dr Wucherer goes on to say that on reaching home he carefully looked up the literature of the subject. “In a ‘Geologico-Medical Report’ by Professor Hirch, recorded in the ninety-sixth volume of ‘Schmidt’s Jahrbucher,’ I found how Griesinger had recognised the Anchylostoma as the cause of the Egyptian chlorosis, which was clearly identical with our hypoæmia. He had employed this commended anthelmintic. I resolved the more to prescribe the pulp of the Gammeleira when I found it described as a worm-expelling remedy in Martin’s ‘Systema Materiæ Vegetabilis Braziliensis.’ The next morning, however, when I arrived at the monastery I learnt that my patient died about two hours after a slight evacuation. Only after much resistance would they permit the sectio cadaveris. I merely opened the abdomen, and was surprised to find everything as Griesinger had described. During the next season, through the courtesy of my colleagues attached to the General Infirmary at Bahia, especially of Drs Silva Lima, Faria, and Caldos, I was enabled to open more than twenty bodies of anæmically deceased individuals. All were selected as miserably poor in condition, but only five were bodies of persons in whom hypoæmia was diagnosed, and in these there were a great number of Anchylostomes in the small intestine. The intestines of the other bodies contained either none, one, or a few.” Dr Wucherer next states that he compared the characters presented by his entozoa with those given by Dubini, Diesing, and Von Siebold, and found a perfect agreement throughout. He sent several examples to Griesinger, who also established their identity, and communicated the results of his investigations accordingly (‘Archiv für Heilkunde,’ 1866, s. 387. See also Leuckart, ‘Die Mensch. Par.,’ Bd ii, s. 411). Dr Wucherer also forwarded a number of specimens to Dr Weber, who published a brief account of them with excellent figures (‘Path. Soc. Trans.,’ vol. xviii, 1867, p. 274). As mentioned in the text of his memoir (s. 394), Dr Wucherer also transmitted some strongyloids to myself. “The publication of my observations,” adds Dr Wucherer (‘Gazeta Medica da Bahia,’ 1866, p. 27 et seq.), “had a result in that Dr J. R. de Moura, of Thersepolis, in the province of Rio de Janeiro, sought for Anchylostomes in the bodies of tropical anæmics (Hypöæmikern). He at once found these parasites, as stated in the same journal (for 1866, p. 132). As occurred to myself, he saw no enduring results from the application of the remedies which appeared to be called for, whilst he well knew that unprofessional persons (Nichtärzte) succeeded in obtaining marked results by the exhibition of the pulp of the Gammeleira (Ficus doliaria). The anthelmintic action of this remedy was also unknown to him.” Dr Wucherer then records how his discovery of these entozoa was announced by Dr Jobini to the Rio academy, and how Dr Moura’s observations were subsequently communicated, adding remarks upon the interesting discussion that followed. The general opinion was that the Anchylostomata were not the primary and necessary cause of this tropical anæmia, but rather a co-operating agent in its production. Against this view Dr Wucherer afterwards very properly protested (‘Gazeta,’ Jan. 15th, 1868). In the mean time, says our author, “Dr le Roy de Méricourt, prompted by my first communication, had invited the physicians of the French colony to seek for Anchylostomes. Drs Monestier and Grenet, at Mayotta (one of the Comoro Isles, which lies about 12° S. lat. to the north-east of Madagascar), ascertained the presence of entozoa in hypoæmics. Dr Grenet sent the duodenum and a portion of the jejunum of an hypoæmic corpse to Le Roy de Méricourt, who compared the Anchylostomes with Davaine’s description, and recognised them as examples of A. duodenale.”

“In the year 1868 Dr Rion Kérangel found Anchylostomes in the bodies of hypoæmics in Cayenne. Thus, the occurrence of Anchylostomes in hypoæmics has been authenticated by Pruner, Bilharz, and Griesinger, in Egypt; by myself, Dr Moura, Dr Tourinho, and other physicians, in Brazil; by Monestier and Grenet, in the Comoros; and by Rion Kérangel in Cayenne. It thus also appears, from the wide separation of these several localities, that the Anchylostomes, if duly sought for, will be found in many other countries.”

These details given by Wucherer are so precise and instructive that I could not have further abridged them without injustice to his record. The bearing of the foregoing facts in relation to the question as to how we may hope to arrest the fatal action of many of these nematodes is sufficiently obvious. That strongyles and their allies prove highly destructive to man and beast is as well established as any other recognised conclusion in medical science; nevertheless, there are those who still doubt the power of these nematodes in relation to the production of fatal epidemics. I shall deal with the sanitary bearings of the subject hereafter. In conclusion, I may mention that Dr da Silva Lima has forwarded specimens of Anchylostomum to the Hunterian Museum, where they may be seen.

Bibliography (No. 29).—Bilharz, ‘Zeitschr. f. wiss. Zool.,’ Bd. iv, s. 55.—Cobbold, ‘Entozoa,’ p. 361.—Idem “Remarks on Recent Contributions to our Knowledge of the Parasitic Nematoids, especially in reference to the Wasting Diseases they produce in Man and Animals,” the ‘Veterinarian,’ Jan., 1876, p. 1.—Davaine, l. c., pp. 118 and 931.—Diesing “Revis. der Nematoden,” ‘Sitzb. d. m.-naturw. cl. d. k. Akad.,’ 1860, s. 716.—Dubini, ‘Entozoografia,’ &c., 1849.—Griesinger (quoted above), see also ‘Arch. f. Phys. Heilk.,’ 1854.—Küchenmeister, l. c., Eng. edit., p. 383.—Leuckart, l. c., ss. 410–455.—Molin, ‘Il sottordine degli Acroffali,’ p. 61 (quoted by Leuckart).—Siebold, ‘Zeitsch. f. wiss. Zool.,’ 1852, s. 55.—Sonsino, P., L’Anchilostoma duodenale in ‘relazione coll’ Anemia progressiva perniciosa,’ Egitto, 1877.—Idem, ‘Sull.’ Anch. duod., 1878 (see also Bibliog. No. 27, both reprinted from ‘Imparziale.’)—Weber, H., l. c., 1867.—Wucherer (quoted above), 1872.

Dracunculus medinensis, Cobbold.—This parasite is popularly known as the guinea-worm, or Medina-worm. Probably Lister was the first writer who distinctly spoke of it as the Dracunculus, 1690, the same title being applied to it by Kaempfer, 1694. Be that as it may, Gmelin, long afterwards, placed the parasite in the genus Filaria, at the same time adopting the specific title medinensis. This had been previously employed by Linneus, who, however, regarded the worm as belonging to the genus Gordius. It being clear from the distinctive characters of the entozoon that it was desirable to separate it from the Filariæ, and that no better generic name could be devised than Dracunculus, I thought it right to combine Lister’s and Gmelin’s nomenclature as above, 1864. Leuckart pursued a similar course, crediting Linneus with the titles.

The guinea-worm having been known from the earliest times, it is not surprising that its true nature long remained a mystery. Any one who has read Küchenmeister’s elaborate narrative of the historical significance of the Dracunculus will hardly have failed to arrive at the conclusion that Moses was probably the earliest writer on the endemic disorder which is occasioned by this parasite. There can be no doubt that the “fiery serpents” which afflicted the children of Israel during their stay in the neighbourhood of the Red Sea were neither more nor less than examples of our Dracunculus. It is further evident that Plutarch spoke of Dracunculi, when in the eighth book of his ‘Symposiacon,’ he quotes Agatharchidas as stating that the people taken ill on the Red Sea suffered from many strange and unheard-of attacks, amongst other worms, from “little snakes, which came out upon them, gnawed away their legs and arms, and when touched retracted, coiled themselves up in the muscles, and there gave rise to the most insupportable pains.” In order to render the passage more readable, it will be seen that I have slightly altered the original version (‘Parasites,’ s. 305).

The guinea-worm may be described as a nematode measuring from one to six feet in length, having a thickness of 1/10th of an inch. The body is uniformly cylindrical, terminating below in a more or less curved and mucronately pointed tail. The head is flatly convex or truncate, having a central, simple mouth, which is surrounded by four equi-distantly and cruciately disposed papillæ. The mode of reproduction is viviparous, the body enclosing a prodigious number of hatched embryos, which, by distension of the uterine ducts, almost entirely obliterate the somatic cavity. Notwithstanding the statements of Owen to the contrary, the male Dracunculus is at present altogether unknown.

The guinea-worm possesses a comparatively limited geographical range, for not only is it proper to the tropical regions, but within intertropical limits it is almost exclusively confined to certain districts in Asia and Africa. Thus, according to Künsenmuller, as quoted by Busk, it occurs endemically in Arabia Petræa, on the borders of the Persian Gulf and Caspian Sea, on the banks of the Ganges, in Upper Egypt, Abyssinia, and the coast of Guinea. “In America the guinea-worm is unknown, except in persons who have had communication with Africa or other parts where it is indigenous. The island of Curaçoa is the only locality in the New World which offers an apparent exception to this fact, and it would be highly desirable to ascertain the real state of the case in this instance.” The observations of Chisholm showed that the Dracunculus is really prevalent in several of the West Indian islands, especially in Grenada, and the still later investigations of Dr Da Silva Lima point to its former prevalence in Brazil. Now, the worm is rarely seen at Bahia. Mr Busk said:—“Though endemic only in the above-mentioned parts of the world, it would yet appear that all races of mankind are obnoxious to the attacks of the Filaria when exposed to what may be called the contagion; that is, when placed in circumstances under which it might be supposed a contagious seminium could be conveyed to them.” Mr Busk also added:—“I have known many instances tending to prove that, in order that a European should become infected with the guinea-worm on the coast of Africa, it is not necessary that he should have been on shore at all. It has been quite sufficient for him to have exposed the bare surface of some parts of his person to the water in the native canoes alongside, or, it may be, to the discharge from the sores of those laboring under the disease. This mode of its introduction accounts for the frequency with which the legs and feet are attacked by the parasite, in preference to other parts of the body, as it will always, I believe, be found that the men who have become so affected have been in the habit of going about with bare feet, as is common among sailors in warm latitudes. That the contagious material is conveyed in water is also further indicated by the well-known fact that in India, where it is the custom of the natives to carry water in skins on their backs, the worm makes its appearance on the back and shoulders and upper part of the body.” These views were published by Busk in 1846, and I am free to confess that—confirmed as they appeared to be by subsequent and independent testimony—they completely dominated my conceptions as to the mode of ingress of the young parasites within the human bearer. Thus, those of our Indian troops which were most exposed during the rainy season, subsequently exhibited evidence of having been invaded by the Dracunculus. As, moreover, the period of incubation of the entozoon commonly extends from twelve to fifteen months, it necessarily happened that the disease often showed itself in localities far distant from the spot where the troops originally contracted the disorder. The statement that the period of incubation of the worm is not less than a year, is probably incorrect, since Carter mentions that in a school of fifty boys bathing in a certain pond at Bombay—the sediment of which swarmed with microscopic tank-worms (Urobales palustris, Carter)—twenty-one were attacked with Dracunculus during the year, whilst the boys of other schools, bathing elsewhere, remained, with few exceptions, uninfected. This is a remarkable occurrence, and it points to the possibility of the young Dracunculi being confined to particular pools. That they should, whether occupying the bodies of intermediary bearers or not, be more abundant in some waters than others, is just what might be expected, since such a distribution is in harmony with a recognised law affecting the abundance or limitation of species in particular localities. Much, indeed, has been written respecting the nature of the soil and geological formations occurring in the Indian worm-districts, but the speculative views enunciated on this point are little worthy of credit. Those who desire information on this head should at all events consult the valuable writings of Smyttan, Greenhow, Bird, Forbes, Chisholm, and Aitken, who, apart from the question at issue, supply abundance of practical information.

Into the anatomy of the adult Dracunculus I do not enter, but I may remark in passing, that the structure of the worm has been exhaustively treated of by Busk and Bastian. A résumé of their views is given in my introductory treatise. Carter and Leuckart have also added important details. As regards the structure and development of the young worms, I have to observe that the discovery of the viviparous mode of reproduction in Dracunculus is due to Jacobson. Nearly a quarter of a century ago I recognised the fact that the uterine organs of the adult worm almost completely filled up the perivisceral cavity, and that they were crowded with microscopic worms. Referring to this “find,” the late Sir George Ballingall, of Edinburgh, in his well-known work on ‘Military Surgery,’ recorded the circumstance in the following terms:—“The Assistant Conservator of the Anatomical Museum in our University has detected in the oviduct of an adult specimen from my collection myriads of minute and perfectly-developed (embryonic) Dracunculi. They can be very well seen with an half-inch object-glass, but their structure is best exhibited if the magnifying power be increased to two hundred and fifty diameters linear.” As already stated in my introductory treatise, these observations were made during the winter of 1853–54. In July, 1854, M. Robin made a similar statement after examining a fresh Dracunculus which had been extracted from the leg of a man by M. Malgaigne. Robin, not unsuitably, compared the worm to a double tube, one tubular sheath, as it were, enclosing the other. “The second tube,” he distinctly affirms, “is the oviduct, or, rather, that part which represents the uterus. The young still remaining in the uterus were nearly all coiled, sometimes with the tail sallying outwards, at others rolled like the rest of the body.” I have thought it only due to Robin and myself to show that from the first we were perfectly well acquainted with the fact of the “great development of the genital tube and of its close adherence to the parietes of the body.” To be sure, many discrepancies occurred in our writings, and in those of Busk and Carter. It was Bastian’s skill and good fortune to correct these errors. Thus, most of us agreed in recognising a slightly trilobed or tripapillated mouth; but Carter failed to demonstrate the existence of these tubercles, and spoke of the oral aperture as being simple and “punctiform.” The body throughout its three upper fourths appeared to me to be cylindrical, but Robin found that it was flattened. It is finely striated transversely, except at the part where it contracts to form the slender, pointed tail. According to Carter, Robin, and Davaine, the young attain a length of about 1/33 of an inch, but Bastian gives it as about 1/42″. In thickness, Carter gives the approximative diameter as 1/633″, Robin makes it 1/990″ to 1/1320″, whilst Bastian gives their breadth at 1/1428″, and Davaine at 1/2500″. I estimated their greatest length and breadth to be 1/30″ by 1/1000″. Robin and myself thought we recognised a distinct, rounded, anal orifice; and whilst Busk, on the one hand, saw nothing which in the slightest degree indicated the presence of an anal opening, Carter, on the other hand, described the structure which we called the anus as a gland, at the same time placing the alimentary outlet on one side and a little above it. According to Bastian, “the intestinal tube is about 1/87″ in length, and appears to consist of a simple canal of varying calibre, pursuing a nearly straight course, and terminating exactly at about the middle, in length, of the worm.” Like Robin, Bastian recognised œsophageal and stomachal divisions, and in a few examples he observed the cæcal or terminal portion of the intestine to be partially reflected upon itself. In regard to the circular opening which Robin and myself described as the anus, Bastian says there is a rounded body, “about 1/2200″ in diameter, with a dark or light spot in the centre, according to the varying focal distance, and which seems to represent a central aperture. Sometimes, above this, traces of two or three large cells may be recognised, whilst behind nothing definite can be made out, save that the cavity of the body is visible for about 1/400″. In other specimens of the young worm the central body and spot are wanting, but, in its stead, two lateral sacculi are met with, about 1/3300″ in diameter, that communicate with the exterior by a minute channel through the integuments, which can sometimes be distinctly recognised. At other times the channel is obscured by protrusion, which appears to have taken place through it, of a minute bilobed papilla, projecting 1/10,000″ from the side of the body. When the projections are seen, the sacculi are indistinct.”

As Bastian found the young in all stages of development from the germ condition 1/5000″ in diameter up to the perfect embryo, and as, moreover, he, like the rest of us, could detect no sexual orifice in the adult Dracunculus, he was led to express his belief that the young were produced agamogenetically. He went so far as to call the germs pseudova. It was with great reluctance that I dissented from the views of so gifted an observer as Bastian; nevertheless, later researches have shown that I was justified in not hastily concurring in the theory of a non-sexual mode of reproduction for Dracunculus.

Among the many advances of modern helminthology, the discovery of the true source of the guinea-worm is not the least important. To the late M. Fedschenko (the lamented and accomplished Russian traveller, who lost his life in a snowstorm on the Alps), science stands indebted for this memorable advance. Fedschenko showed that the embryos of Dracunculi, after quitting the human host, succeed in effecting an entry into the bodies of entomostracous crustaceans belonging to the genus Cyclops. Within these intermediary bearers, after twelve hours’ sojourn, the embryos undergo a change of skin, attended with subsequent growth. Here they remain to complete their larval development, which takes place within a period of five weeks, or, as Fedschenko himself told me, one month and six days. At length, as perfected larvæ, they are, together with their crustacean hosts, transmitted to the stomach of the ultimate or human bearer. It is probable that sexual maturity is next acquired within the human stomach, copulation following. After this, the females migrate to the situations in which they are found beneath the skin of the human bearer, whilst the males perish and pass out with the fæces. Thus much I gathered from M. Fedschenko himself when he visited this country, and I possess a sketch of the larvæ made by him at the time (October 23rd, 1873). One of the figures represents a larva which has undergone ecdysis, the long and narrow embryonic tail being supplanted by one which is blunt and forked at the tip. The somatic contents of the embryo have at the same time differentiated into a complete intestinal tube, and a constriction marks the junction of the œsophagus with the stomach. There is also internally an oval-shaped mass of cells near the centre of the body. These represent the commencement of the reproductive organs.

What I had gathered from Fedschenko in conversation thus epitomises that which has since been much more fully stated by Leuckart; and it is only fair to add that the Russian traveller was led up to his discovery by the previous investigations of Leuckart respecting the young of Cucullanus. The Leipsic helminthologist had, indeed, specially instructed Fedschenko as to the probable source of Dracunculus.

It is often thus that science makes its clear advances, since a master-mind is needed to set others on the right track. The embryos of Cucullanus and Dracunculus bear a close resemblance to each other, and the similarity of the types is continued on, though not in the same degree, in the next stage of larval growth, after ecdysis. The higher larvæ of both have their tails trifurcate at the tip, the head of the Dracunculus-larva being distinguished by the presence of a pair of papillæ. In the case of Cucullanus the embryos are, according to Leuckart, passively transferred to the stomach of Cyclops by the mouth; but in the case of Dracunculus, Fedschenko saw the embryo in the act of perforating the bodies of the little crustacea at the ventral surface, where the segments are bound together by a thin and easily penetrated connecting membrane. The larvæ then proceed to coil themselves within the limbs, as many as six or even a dozen of the parasites being occasionally found within the body of a single crustacean host. When they have reached full larval growth they measure about 1/25″ in length. Of course, after attaining this stage, it is a matter of conjecture as to the precise way in which their final destiny is accomplished. Fedschenko fed dogs and cats with the infected crustacea, but failed to rear Dracunculi in these animals. Clearly, these carnivora were unsuitable hosts. Could Fedschenko have experimented on man the result would probably have been very different. Arguing from what happens in the case of Cucullanus amongst fishes, and Trichina in man, there can be little doubt that all the further and final changes undergone by the larvæ are accomplished within the human host. These changes are usually, if not invariably, consequent upon a direct transference of the infested entomostraca along with water used as drink. Thus, it must at once be evident that the simple sanitary precaution of filtering water before use is amply sufficient to ensure the prevention of attacks of dracontiasis or the guinea-worm disease. The theosophical remedy of Moses against this invasion by fiery serpents, as the worms were called in his time, and the modern prophylactic measures dictated alike by science and common sense, thus stand in striking contrast the one to the other. In the nature of things it must ever remain that unreason and reason will select diametrically opposite methods of action, equally, no doubt, with the good intention of bringing about beneficial results.

From what has now been advanced, it will be seen that as regards the mode of infection the views categorically expressed in my previous work (‘Entozoa,’ p. 387) cannot be maintained. What, however, is there stated in respect of treatment still holds good in the main, even as regards prophylaxis.

Bibliography (No. 30).—Adam, ‘Trans. Med. and Surg. Soc.,’ Calcutta, 1824.—Aitken, W., ‘The Science and Practice of Medicine,’ 6th edit., vol. i, 1872.—(Anonymous), “Review of the writings and opinions of Duncan, Johnson, Bird, Mylne, Kennedy, Chisholm, H. Scott, A. J. Robertson, Smyttan, Macgregor, Thomas, Mosely, Morehead, Twining, and others, on the Dracunculus or Guinea-worm,” in ‘Corbyn’s India Journ. of Med. and Phys. Sci.,’ vol. ii, p. 118, 1836.—(Anon.), “The Guinea-worm very Prevalent at Bokhara,” ‘Boston Med. and Surg. Journ.,’ 1843, p. 387.—Balfour, J., ‘Ind. Ann. Med. Sci.,’ 1859, p. 175.—Ballingall, G. (l. c., supra), 1854.—Bastian, H. C., “On the Structure and Nature of the Dracunculus or Guinea-worm,” ‘Linn. Soc. Trans.,’ vol. xxiv, p. 101, 1863.—Berncastle, J., in the ‘Lancet,’ 1851.—Bird, J., ‘Calcutta Med. and Phys. Trans.,’ 1825, p. 151.—Bremser (l. c., Bibl. No. 2), s. 194.—Brett, ‘Surgical Diseases of India,’ 1840; see also ‘Med.-Chir. Rev.,’ 1841.—Bruce, N., ‘Edin. Med. and Surg. Journ.,’ 1806, vol. ii, p. 145.—Busk, G., ‘Micr. Soc. Trans.’ (original series), 1846.—Carter, H. J., “Note on Dracunculus in the Island of Bombay,” ‘Bombay Med. and Phys. Soc. Trans.’ (new series), No. 2, p. 45, 1853–54; see also postscript, p. 252.—Idem, “Further Observ. on Dracunculus,” ‘Bomb. Med. and Phys. Soc. Trans.’ (new series), No. 4, p. 215, 1857–58.—Idem, “On Dracunculus and Microscopic Filaridæ,” ‘Ann. of Nat. Hist.,’ vol. iv (third series), 1859.—Idem, “Notes on Dracunculus,” &c., ‘Ann. of Nat. Hist.,’ vol. ix (third series), 1862.—Chapotin, ‘Bull. des Sci. Med.,’ 1810.—Charvet, ‘Ann. des Sci. Nat.,’ 1834.—Chiaje (l. c., Bibl. No. 2), p. 99.—Chisholm, C., “On the Malis Dracunculus or Guinea-worm (in Grenada),” ‘Edin. Med. and Surg. Journ.,’ vol. xi, 1815; see also the ‘Veterinarian,’ vol. ix, p. 508, 1836.—Clark, ‘Med.-Chir. Rev.,’ 1840.—Clarkson, N. F., “Alleged Case in the Horse,” the ‘Veterinary Record,’ 1845, p. 73.—Clot-Bey, ‘Aperçu sur le ver dragonneau observé en Egypte,’ 1830.—Cobbold, ‘Entozoa,’ p. 373.—Cuvier, ‘Règne animal,’ Orr’s Eng. edit., 1849, p. 644.—Davaine, ‘Traité,’ l. c., edit. ii, p. 783 (full lit. refs.), 1878.—Dickson, ‘Path. Soc. Trans.,’ 1851.—Drummond, ‘Med. Commentaries,’ 1793, p. 294.—Dubois, ‘Edin. Med. and Surg. Journ.,’ vol. ii, 1806.—Duncan, ‘Calcutta Med. and Phys. Soc. Trans.,’ 1835.—Ewart, J., “Questions relating to Dracunculus,” in a review of his memoir on the “Vital Statistics of the Meywar Bheel Corps,” in the ‘Madras Quart. Journ. of Med. Sci.,’ vol. i, 1860, p. 462.—Fedschenko, ‘Protocol of the Promoters (Freunde) of the Natural and Physical Sciences at Moscow’ (in the Russian language), 1869 and 1874 (quoted by Leuckart).— Forbes, D., “Observ. on Dracunculus” (extr. from the ‘Half-yearly Reports of the diseases prevailing at Dharwar in the 1st Grenadier Regiment, in the year 1836’), ‘Bombay Med. and Phys. Soc. Trans.,’ vol. i, 1838, p. 215.—Gibson, A., “Note on the Prevalence of Dracunculus,” in his remarks on the “Diseases of the Deckan,” in ‘Bomb. Med. and Phys. Soc. Trans.,’ vol. ii, 1839, p. 209.—Gramberg, ‘Geneeskundige tijdschrift voor nederl. Indie,’ 1861, p. 632 (quoted by Leuckart).—Greenhow, H. M., ‘Indian Ann. of Med. Sci.,’ vol. vii, 1861, p. 31.—Grierson, D., “Observ. on the Dracunculus, as it prevailed in the 22nd Regiment, N.I., from April till September, 1841,” ‘Bomb. Med. and Phys. Soc. Trans.,’ No. 4, 1841, p. 90.—Grundler, in ‘Commerc. Litt. Nov.,’ 1740, p. 239.—Henderson, J., “Note respecting Four Cases of Dracunculus in the 48th Regiment,” ‘Madras Quart. Journ.,’ vol. iii, 1841, p. 353.—Horton, J. A. B., ‘Army Med. Reports,’ 1868, p. 335.—Kennedy, R. H., ‘Calcutta Med. and Phys. Soc. Trans.,’ 1825, p. 165.—Küchenmeister (l. c., Eng. edit.), p. 389.—Leuckart (l. c., Bibl. No. 1), s. 644–725.— Lewis, T. R., in ‘On a Hæmatozoon,’ &c. (l. c., Bibl. No. 23), p. 30 et seq.—Lima, Da S., “Remarks on the Filaria medinensis, or Guinea-Worm; on the occurrence of this Parasite endemically in the Province of Bahia; on its entrance into the human body by drinking water,” in the ‘Veterinarian,’ Feb., March, et seq., 1879.—Lister, ‘Phil. Trans.,’ 1690, p. 417.—M’Clelland, J., ‘Calcutta Journ. of Nat. Hist.,’ vol. i, 1841, p. 366.—M’Grigor, J., “On the Guinea-worm” (in his “Account of the Diseases of the 88th Regiment in Bombay”), ‘Edin. Med. and Surg. Journ.,’ vol. i, 1805, p. 284.—Morehead, C., ‘Calcutta Med. and Phys. Soc. Trans.,’ vol. vi, 1833, p. 418; also noticed in ‘Edin. Med. and Surg. Journ.,’ vol. xliv, 1835.—Idem, part ii, ‘Calcutta Med. and Phys. Soc. Trans.,’ vol. viii, 1836–42.—Murray, J., “Guinea-worm a very Common Disease at Sattara” (in his Official Report on the Hospital, &c.), ‘Bombay Med. and Phys. Soc. Trans.,’ No. 9, art. vi, p. 198, 1847.—Oke, W. S., “Case of Guinea-worm,” ‘Prov. Med. and Surg. Journ.,’ vol. vi, 1843.—Oldfield, “Case of Dracunculus” (from Laird and Oldfield’s “Narrative of an Expedition into the Interior of Africa”), ‘Dublin Journ.,’ vol. xii, 1838.—Paton, “Cases of Guinea-worm,” ‘Edin. Med. and Surg. Journ.,’ vol. ii, 1806.—Raddock, “A Case of Guinea-worm,” ‘Indian Med. Gaz.,’ Oct., 1877, p. 265.—Scott, W., “Remarks on the Dracunculus,” in a letter to the Medical Board, Madras, ‘Edin. Med. and Surg. Journ.,’ vol. xvii, 1821.—Leverance, C. E., “History of a Case of Guinea-worm,” from ‘Amer. Med. Times,’ in the ‘Glasgow Med. Journ.,’ vol. ix, 1861–62, p. 377.—Smyttan, G., “On Dracunculus,” ‘Calcutta Med. and Phys. Soc. Trans.,’ vol. i, 1825, p. 179.—Stewart, L. W., ‘Indian Ann. of Med. Sci.,’ vol. vi, 1858, p. 88.—Twining, W., “Cases of Dracunculus,” ‘Calcutta Med. and Phys. Soc. Trans.,’ vol. vii, 1835.

Oxyuris vermicularis, Bremser.—Of all the parasites infesting the human body this is the one concerning which the medical practitioner is most frequently consulted, partly on account of its remarkable frequency in children, and more particularly on account of the difficulty often experienced in getting permanently rid of it. The Oxyuris vermicularis is by no means confined to young persons, seeing that adults are infested even to old age. It is familiarly known as the threadworm or seatworm. The male measures about 1/6″, and the female from 1/3″ to 1/2″ in length. The female possesses a long capillary tail, which terminates in a three-pointed end. The extremity is said to act as a kind of holdfast. The tail of the male is obtusely pointed. In both sexes the body presents a more or less fusiform shape, the anterior end being narrowed to form a somewhat abruptly-truncated head, which is often rendered very conspicuous by a bulging of the transparent integument surrounding the mouth. This presents in profile the aspect of winged appendages (fig. 45). The oral opening is tripapillated, leading into a triangular œsophagus. The integument is transversely striated, and of a silvery-white appearance. The spicule is simple, single, and very minute. The eggs are oblong and unsymmetrical. They measure about 1/900″ from pole to pole, and 1/1400″ transversely.

Many years back (1863) I pointed out that the most advanced eggs whilst still within the body of the pregnant female contained tadpole-shaped embryos, and about the same time the fact was noticed by Claparède. In his beautiful and scholarly memoir, ‘De la formation et de la fécondation des œufs chez les vers Nématodes,’ he wrote concerning the ova as follows:—“The egg, which exhibits the form of a very narrow disk in the ovary, acquires the shape of an elongated ellipsoid in the oviduct, and at the surface differentiates itself into a very thick vitelline membrane. Then it forms a strong and resisting chorion, which imparts to the egg an outline similar to that of a bridge’s span. It has an oval figure flattened at one of its sides. This chorion is very fragile; it frequently gives way under slight pressure from the thin plate of glass which covers the object. It extends itself considerably under the action of acetic acid, acquiring a size three or four times greater than that of the egg. The constitution of this chorion is perfectly identical in the eggs both before and after impregnation. It is, nevertheless, easy at first sight to know whether or not we have to deal with a fecundated egg. In the impregnated females the uteri are filled with thousands of ova, each one of which encloses an embryo already well formed. The ventral surface of the embryo and the tail are, without exception, applied to the flattened side of the egg. The embryo is very broad in the body, and occupies all the interior space. An embryo such as Küchenmeister has represented under the form of a small filiform worm folded on itself, and only occupying a very small part of the cavity of the egg, is never to be seen. In the non-fecundated females, on the other hand, the uteri are filled with eggs, which, instead of the embryo, enclose a non-segmented yolk furnished with a large germinal vesicle. This vesicle is not visible so long as the eggs have the form of thin disks; it only shows itself when the eggs begin to acquire an elliptical form in the oviduct. It is, however, probable that this vesicle is the same which was originally visible in the ovary.” The chorion itself is homogeneous, but in an allied species (Oxyuris spirotheca) Gyoery and Claparède found that this egg-covering consists of spirally-coiled bands resembling the tracheal spiral fibre of an insect. Under suitable conditions the tadpole-shaped embryos rapidly assume a vermiform character. The investigations of Leuckart have shown that “one only needs to expose the eggs to the action of the sun’s rays in a moistened paper envelope when, at the expiration of five or six hours, the tadpole-shaped embryos will have already become slender elongated worms.” According to Heller, the simplest way to rear the vermiform stage of Oxyuris is to put a number of the eggs in a glass tube filled up with saliva. The tube should then be placed in the arm-pit, in which situation it can be carried about with little inconvenience. In a few hours the transformations will commence and go on continuously until the vermiform condition is attained. If, as remarked in my ‘Lectures,’ it be asked whether the embryos which have escaped into the bowel are capable of arriving at the vermiform stage, the answer is in the affirmative; for, as Leuckart says, “the elongated embryos are to be found not only in the fæces but also in the mucus of the rectum above and around the anus.” Vix has also asserted that free vermiform embryos are occasionally to be detected in the intestine of the human bearer along with the eggs; this hatching within the lower bowel, however, must, in my opinion, be regarded as exceptional. Heller is of the same opinion. According to Leuckart, the escape of the embryos from the eggs “ordinarily takes place under the action of the gastric juice, also primarily in that condition when they have by some means or other gained access to a new bearer.” Prof. Leuckart and three of his pupils courageously infected themselves by swallowing the eggs, and had the satisfaction of observing young Oxyurides in their stools fifteen days afterwards.