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Library. The Committee also have to thank the following donors of books to the Library:-
The Director of Colombo Museum, The Director of the Laboratorio di
Zoologia Generale, Portici, Harvard University Press,
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"The Snakes of Ceylon, by Wall, 1921". "Monografia delle Cocciniglie Italiane." by Leonardi, 1920.
"Etiology and Pathology of Typhus," by Wolbach, Todd and Palfrey, 1920.
Entomological Department.-Apart from the teaching of the medical and veterinary students attending this School, a considerable amount of original work has been done largely in connexion with the speciographic, bionomic and morphologi- cal aspects of various blood-sucking insects. A list of the published papers dealing with these subjects appears elsewhere in this report.
Dr. J. W. S. Macfie and Dr. A. Ingram have continued their joint work on the Ceratopogonine midges of the Gold Coast and have published the results of their investigations in the Annals of this School.
At the request of the Liverpool Port Sanitary Authorities a ship from West African ports, said to be badly infested with mosquitoes, was examined with negative results.
Extensive collections of various blood-sucking insects have been received for determination and report from various parts of the world, chiefly from the Congo Free State, the West Indies, Venezuela and Brazil. The new and undescribed mosquitoes, tsetse-flies, and pappataci flies included in these collections have been described and figured.
Certain other insects of economic importance received from various institutions in Liverpool have been reported upon to the various authorities concerned.
Large numbers of mosquitoes have been bred in the laboratory for experimental and teaching purposes. Eggs of Stegomyia fasciata sent over from the laboratory of Dr. H. W. Thomas in Mandos, were raised to adults which laid eggs, and eventually eggs were obtained from the third generation of adults.
Living examples of the Venezuelan reduviid bug (Rhodnius prolixus) have been successfully reared to the second generation.
Sierra Leone Research Laboratory. This laboratory, which was opened on 10th January, 1922, is a two-story building situated 200 feet above sea level on Tower Hill overlooking Freetown, a site placed at the disposal of the school by the War Office.
The staff consists of the director, D. B. Blacklock, M.D., Professor of Tropical Diseases of Africa, and two research assistants, S. Adler, M.B., Ch.B., and E. J. Clark, M.C., M.B., Ch.B., D.P.H.
Án account of the investigations completed, or in progress, are given in a report from the director:
Malaria. Soon after our arrival my colleague, Dr. Adler, and I discovered in a chimpanzee a malaria parasite which presents features of interest. Its interest lies in the facts that it is a parasite which not only causes acute illness in the chimpanzee, but also cannot be distinguished morphologically from the parasite which causes malignant tertian malaria in human beings. Regarding the matter as one of importance to malariologists, we carried out experiments designed to prove whether or not this parasite was (1) transmissible to human beings by injection of blood; (2) capable of producing infection in anopheline mosquitoes.
In order to determine the first point, we injected heavily-infected blood into the sub-cutaneous tissue and also into the veins of two Europeans. Neither of these became infected with malaria. The conclusion arrived at was that either this was not the human parasite, or else it was the human parasite existing in low state of virulence.
In order to determine the second point, laboratory-bred Anopheles costalis were fed on the animal, and subsequently dissected in order to trace infection in the mosquito. The results of the experiment were negative and tended to support the conclusion arrived at by the first experiments.
For many reasons, however, these latter experiments required amplification and repetition, but unfortunately the chimpanzee succumbed to an intercurrent disease before we could repeat the experiments. We are engaged in trying to procure further animals for examination, but they are difficult to obtain, and the cost is an important consideration.
Helminthiasis: (1) Strongyloides: Great importance is attached by us to the cause of death of the chimpanzee mentioned above. The animal died suddenly owing to the invasion of the lungs by the larve of a nematode worm of the genus Strongyloides. Although it has been known for many years that the larvae of certain nematodes which infect man and animals are capable of penetrating the unbroken skin of man and reaching the lungs, remarkably little attention has been paid to the study of lesions which such larvæ cause in the lungs and other organs. Stewart's recent work on Ascaris has stimulated interest in the pathological conse- quences which follow invasion of the organs, especially the lungs, by the larvæ of A scaris. Records, however, of the results which follow such invasion in nature are almost entirely lacking.
With reference to Strongyloides, the discovery that severe symptoms and even a fatal result may be caused by the larvæ is particularly interesting because of two facts:-
1. Strongyloides infection is frequently regarded as a matter of little importance.
2. Strongyloides infection is extremely difficult to eradicate. Our observations, therefore, clearly point to the necessity of regarding Strongy- loides infection as a serious condition which will require further investigation; we have obtained evidence that the adult Strongyloides also is by no means innocuous, as it caused well-marked chronic inflammatory changes and also tumour formation in the jejunum of the chimpanzee. In view of the greater difficulty of cure, Strongyloides may come to rank in tropical sanitation as more important than even Ancylostoma and Necator.
Lung lesions in domestic animals produced by nematode larvæ.-From the conditions present in the case of Strongyloides infection in the chimpanzee, we were naturally led to investigate the conditions of the lungs in other animals. For the purpose of obtaining information which might lead to conclusions possibly applicable to human beings, it was necessary for us to examine dogs and cats. Resort to examination of animals was had because of the fact that in this country opportunities of examination of children after death are so rare as to be negligible. The most direct and valuable method being, therefore, not available, we were compelled to draw conclusions which appear to us legitimate from our findings in the domestic animals examined.
Of twenty-five dogs collected at random from the town, all had hemorrhages in the lungs, and the older dogs had lesions also, such as emphysema and fibrosis of patches of lung. They had all infection of the intestine with ancylostomes and generally ascaris and cestodes were also present; of five cats all presented similar lesions. Larvæ of nematodes were found in the lungs of two dogs and in the trachea of two dogs and one cat. In the absence of evidence to the contrary, we must assume therefore that similar infection is produced in human beings. If we admit this assumption, we cannot avoid the conclusion that the rôle played by larval invasion of the lungs of human beings must be an important one, not only in the immediate effects produced, but also in the after effects. More especially would we expect to find the pathogenic effects produced in children to be more grave, in view of certain evidence which we have obtained from the study of animals, that in small animals relatively few larvæ reaching the lungs may suffice to cause death.
(2) Ancylostomes survey. Dr. Adler has been engaged in carrying out a survey in animals. Infection with adult ancylostomes has been found in very young dogs a fortnight old, which points to intrauterine infection. All dogs examined were infected, two species, A. caninum and A. ceylanicum being found. Ancylos- toma duodenale has also been found in civet cats, and also in a genet.
Mosquito surveys.-An investigation is being carried out by us on the preva- lence of anopheline mosquitoes in native houses. An area of the town adjacent to one of the streams has been chosen, and in this area a number of houses are being examined systematically month by month.
British Medical Association.-There has been founded in Sierra Leone a branch of the Association, and the branch did the director of the Laboratory the honour of inviting him to deliver an address at its first scientific meeting. The meeting took place on the 12th of May, and the subject chosen was "Some Problems of Tropical Medicine." An exhibit prepared by Drs. Adler and Clark was shown. illustrating by naked eye specimens and microscopical preparations, some of the results of our investigations here.
D