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Entomological Department.

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Ships' Disinfection. As the use of Hydrocyanic Gas is coming into favour for the disinfection of vessels, the Liverpool Port Sanitary Authority has made arrange- ments for an investigation to be carried out, jointly with the City Analyst, to ascertain precisely what effect the gas has on various kinds of insects together with their eggs and larvæ. The results of this investigation will be embodied in a later report.

Much time has been devoted to the preparation of an extensive monograph which it is hoped may be completed towards the end of the year.

Collections of mosquitoes and other blood-sucking Arthropods numbering over 700 specimens have been sent to us for determination. These came from the follow- ing countries: Africa (chiefly the Congo Free State), South America and China.

The following investigators have been given facilities and free tables for study and research

(1) Dr. A. Ingram. West African Medical Service. In continuation of his joint investigations on the Ceratopoginine midges of West Africa.

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(2) Dr. J. W. Scott Macfie, West African Medical Service. In continuation of his joint investigations on the Ceratopoginine midges of West Africa. December, 1922, to April, 1923.

Sierra Leone Research Laboratory.

Professor Blacklock's Report 30th November, 1922. Malaria.-"The investigation on the malaria parasite discovered in a chim- panzee has been continued so far as was possible with the funds available. My colleague Dr. Adler proceeded up country on the 23rd of August in order to examine as many chimpanzees as possible and also to bring back to the Laboratory such infected animals as could be purchased so that the mosquito or other vector which conveys the disease might be sought by experimental feeding. His findings proved of great interest and are now in the course of publication. He was successful in discovering several chimpanzees infected with what we have stated to be a parasite identical with the human parasite. Further, he was able to form the opinion that the infection is common among young chimpanzees, but that in older animals it has died out or become so mild as to be difficult of recognition. In this respect it is comparable to the infection as found among the natives of the country, a fact which may prove of value in bringing it still further into line with the human parasites.

Of several chimpanzees which he was able to bring down to Freetown, two contained parasites in the crescent form, but unfortunately the numbers of the crescents were small, and it was not found possible to carry out experiments with mosquitoes before the crescents had fallen to such low numbers as to render success improbable. This is a piece of valuable research which remains to be done in the future and which only awaits funds for its pursuit.

Acute ascending paralysis.--One of the chimpanzees immediately after being captured developed signs and symptoms of a condition of paralysis known in man as acute ascending paralysis. Observations were made of the condition and a paper on the subject has been prepared by Drs. Adler and Clark. The condition is a rare one in man, and so far as I am aware has never before been known to develop in the chimpanzee. The chief interest lies in the fact that the condition arose in a wild chimpanzee just after capture, although there was no evidence of injury during capture, nor was it attributable to dietetic causes after its capture.

Other facts of importance concerning the diseases to which the chimpanzee is liable in nature and in captivity have been collected and will be published.

Helminthiasis. Further study of the helminth infection of man and animals has been made and has yielded results of some value. It is clear, however, that so long as it remains impossible to carry out examination on those who die in infancy and early childhood only indirect evidence from animal examination can be obtained. From this side considerable progress has been made.

Tsetse Fly-I mentioned in the previous report that it was proposed to investi- gate the fly on the Cape Lighthouse Peninsula. During July and August I visited this place and made dissection of 471 flies. The examination proved that the fly was present in numbers, and that it was still infected to the extent of 5 per cent. with trypanosomes. This being so it is now proposed to make a drastic clearing of the breeding places and try not only to eradicate the fly. but also to prevent its re-establishing itself. The means proposed are, after clearing, to plant suitable crons which will not afford the shelter necessary to the fly for breeding. Should

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the attempt prove successful it may be possible to utilize the Cape Lighthouse Peninsula for cattle. This would confer a considerable benefit on Freetown. report on this investigation has been prepared and submitted to the Government. It contains an account of the investigations carried out and the recommendations for dealing with the situation are set out in detail.

Beriberi. I have been afforded the opportunity through the kindness of the Civil Medical Authorities of investigating this disease as it occurs in Sierra Leone, and am at present engaged in endeavouring to assign the causes which have led to the occurrence of this disease and to suggest, if possible, the means by which its recurrence may be prevented.

Rat Investigation.-Freetown has in the past enjoyed an immunity from plague which could hardly be accounted for, either by the absence of overcrowding or by the absence of rats. The presence of the flea carriers of plague and the areas of the town which are most infested by rats are subjects which are at present engaging our attention. It was found that the distribution of rats and plague fleas is such as to afford a ready means for the spread of plague, and we arrived at the conclusion that the most probable explanation of the freedom from plague is the fact that ships do not as yet tie up alongside but lie out in the harbour.

The Civil Medical Authorities have long been alive to the dangers which may follow the construction of a deep-water wharf, and are co-operating in this investi- gation. Dr. Clark joined the Staff of the Laboratory early in April and worked there up to November when he was invalided home and resigned his appointment.

(Professor Blacklock's Second Report at end.)

Publications.

Adler, S. Malaria in Chimpanzees in Sierra Leone.

Ann. Trop. Med. & Parasit., Vol. XVII, No. 1, p. 13. Thirteen chimpanzees were examined for malaria in Sierra Leone. Two young animals were found to be infected with a parasite indistinguishable from P. falciparum. Older animals were negative, and resistance following attacks in early life is, therefore, suggested. Blood from one chimpanzee containing only crescents failed to infect another chimpanzee. Both infected animals on post-mortem examination showed fatty changes in the liver.

Adler, S., and Clarke, E. J. Intra-uterine infection with Ancylostoma caninum

in Dogs.

Ann. Trop. Med. & Parasit., Vol. XVI, No. 4, p. 353. Owing to lack of human material, a number of young animals were examined in order to find whether intra-uterine infection with hook-worms is a common occurrence.

Thirteen young dogs (from two to fifteen days old), representing eight different litters, were examined for ancylostomes.

It appears that in Freetown, where intense infections with A. caninum are the rule with dogs, intra-uterine infection is common. It is noteworthy that, although infection with A. ceylanicum is common in adult dogs, we have not found evidence of intra-uterine infection with this parasite.

Blacklock, B. The Etiology of Blackwater.

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Ann. Trop. Med. & Parasit., Vol. XVII, No. 1, p. 79. The term "Blackwater" Fever, being applicable only to conditions in which hæmoglobin is present in visible quantity in the urine, is too

restricted.

The importance of pre- and post-hæmoglobinuria states which are inherent parts of the disease, is apt to be lost sight of owing to the exclusive use of the term "Blackwater" Fever. Some such term as "Occult" or "Sublimal" Blackwater Fever might be used to express these conditions.

A differentiation of Tropical Hæmoglobinurias into Malaria. Quinine and specific Blackwater types is not possible merely on the basis of the presence and degree of jaundice, or on the relative severity of the signs or symptoms. The existence of a parasitic cause of Black- water Fever has been frequently suggested; an experimental hun an inoculation, with blood from a severe case of Blackwater which ended