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5. Infection actually takes place both by the mouth and through the skin.
Recently contaminated moist earth or water is not infective.
6. Infection in Cairo is acquired most probably from the unfiltered water supply, which is still delivered, in addition to filtered water, to many of the houses, and is drawn from the Nile near where troops are known to have been infected while bathing.
In Part 2 certain peculiar features in the physical conditions of Egypt are detailed, and it is considered that, if properly exploited, almost complete eradication of the disease might result in the course of a few years.
It was noticed that during the summer months the water in the canals in the country around Cairo was periodically stopped. During the periods of stoppage the canal beds became dry. Wherever this occurred there was a great mortality At other parts of the canal, however, owing among the bilharzia-carrying snails.
to irregularity in its bed, sufficient water remained until the flow was renewed to enable the snails to survive. It is pointed out in the report that these parts can be variously dealt with, and that the use of a soluble chemical manure like ammonium sulphate would result in the destruction of the snails, while the manurial value would not be lost, as the salt would be carried on to the fields with the succeeding rotation. In Part 3 the development of the bilharzia parasite in the molluscan inter- This in turn mediary is described. The miracidium changes into a sporocyst. gives rise to several daughter-sporocysts, in which large numbers of cercariæ develop. There is no redia. That the cercariæ penetrate the skin is proved
(a) By the disappearance of the cercaria when a small mammal-e.g., a new- born mouse is suspended in fluid containing large numbers of cercariæ. (b) By the subsequent death of the animal from bilharziasis. (c) By the finding of the cercariæ in sections of the skin.
Finally, the various stages of growth from cercariæ to adult are described and illustrated.
Part 4, now in press, deals with the various molluscs found in Egypt, and gives a description of the larval forms found in them which have to be eliminated in the search for the developmental stages of bilharzia. All the larval trematodes, with one exception, heretofore recorded, and eight new forms were found by us.
With regard to treatment, the results are not yet ready for publication, but it may be stated that so far it has been found that none of the drugs recommended are lethal to the bilharzia worms, even when doses toxic to the host are administered. It would appear therefore that the sole remedy for bilharziasis lies in eradication by eliminating the intermediary hosts, and this is, we believe, as feasible in Egypt as is the eradication of yellow fever by the destruction of its carrier.
Having completed the inquiry in relation to the prevention of bilharziasis amongst the troops in Egypt, I applied for reappointment to the unexpired portion of the Wandsworth Scholarship for 1914, to enable me to return to Egypt to eluci- date the route taken by the bilharzia in its passage from the skin to the portal system, and to complete my researches on the relation of the vesical and intestinal forms of the disease. The War Office has given me the temporary honorary rank of a Lieutenant-Colonel in the Royal Army Medical Corps and is renewing the I have to express my indebtedness to facilities previously enjoyed for the work. the School Committee for permitting me to utilize the opportunity which so unexpectedly occurred for prosecuting this research, and to my colleagues, Drs. J. G. Thomson and R. P. Cockin, for their invaluable co-operation and assistance.
I am, &c.,
ROBERT T. LEIPER,
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No. 134.
REPORT ON BEHALF OF THE LATE PROFESSOR E. A. MINCHIN, M.A., F.R.S., PROFESSOR OF PROTOZOOLOGY IN THE UNIVERSITY OF LONDON, FOR THE YEAR ENDING 30TH JUNE, 1915.
(Received 6th November, 1915.)
By the recent death of Professor E. A. Minchin, F.R.S., the science of proto- zoology suffers the heaviest loss it has had to bear since this branch of zoology rose It is, indeed, into prominence about the beginning of the present century. deplorable that this gifted life, at the height of its powers and activities, should have been brought to an untimely close. Though this is not the place to attempt to offer any tribute of esteem to his memory, I cannot refrain from saying that all who have known him will realize how greatly his kind and ready help and counsel, his thoughtful and stimulating suggestions, will be missed by fellow-workers and students alike. The sad duty devolves on me of endeavouring to indicate the line of research upon which Professor Minchin's attention had been engaged up to the time when his illness developed seriously, and of writing the Report on the general work of the University Department of Protozoology for the past year.
The
Research. Having completed, in collaboration with Dr. J. D. Thomson, the study of the life-cycle of Trypanosoma lewisi in the rat-flea-a study which, it is not too much to say, will rank for all time as the classic account of the life-history of a trypanosome in its invertebrate host-Professor Minchin, on his return from Australia last October, took up, alone, the study of the early changes and develop- ment undergone by T. lewisi on and after its entry into the rat, no observations having been made hitherto upon these early stages. His intention was to supple- ment the knowledge gained of the life-history of the trypanosome in the rat-flea with an equally complete account of its life-cycle in the rat; but, alas! he did not live to proceed far with this even more difficult and laborious part of the research.
The first series of experiments performed was to ascertain the behaviour of the various types of the trypanosome present in the rectum of an infected flea-and especially that of the final, stumpy form-when placed in fresh rat's blood. procedure adopted was as follows:-The rectum of a flea was teased up in salt- citrate solution, on a cover-slip. If stages of the trypanosome were found a drop of fresh blood was added, and the cover-slip was then inverted over a hollowed-out slide, the preparation being sealed up as a hanging-drop preparation. I quote the following record of such an experiment from Professor Minchin's notes :-Rectum of well-infected flea dissected out and mounted with fresh blood from clean rat; the flea was taken from the infected breeding cage, in which there had been a well- infected rat up to six days previously, but during the six days previous to the dissec- tion of the flea only clean rats had been in the cage. When the rectum was mounted it was seen to contain many crithidial forms and final trypanosomes. During the twenty-four hours during which the hanging drop was kept under observation the following forms were noted in it: (1) dividing forms, fairly large, often travelling slowly; (2) small crithidial forms in abundance; (3) "shooters," slender, long, active trypanosomes, travelling at a great pace through the blood, first noted four hours after putting up the drop; (4) little knotted trypanosomes, often two close together, with a peculiar and characteristic type of spasmodic, jerky movement. The pre- paration was smeared off and fixed about twenty-four hours after being put up, there being at the time a few fairly active, slender trypanosomes, but none "shooting rapidly through the blood. In the stained preparation a large number of crithidial forms were found, both nectomonads and haptomonads, the latter being the more abundant; there were also many transitional forms, indicating that transformation of crithidial forms into trypanosomes was going on. The only dividing forms found were crithidial in character; "shooters" were found, and also some little knotted trypanosomes.
In other cases the rectum was teased up and mounted in freshly prepared serum alone. One of these is recorded as follows:-Hanging drop mounted at 11.15 a.m. At 11.45 several trypanosomes seen, all working their flagella, but not travelling. At 3 p.m. many At 12.15 several trypanosomes seen, all sluggish, not travelling. crithidias noted, most of them vibrating actively, some dividing. Trypanosomes also fairly numerous, most of them knotted and showing the characteristic spas- modic movements; many, in pairs, threes, or fours, appearing to adhere together