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results were all positive, but the author points out that dogs of a 

 country where the natural canine disease exists were employed and 

 that although the liver was free, the spleen and marrow may have 

 been infected before the experiment. Realising this possible source of 

 error when experimenting in Malta, he sent over to England for four 

 dogs. Two of these were kept clean in a mosquito-proof cage and to 

 the other two dogs over 300 fleas, captured from infected dogs, were 

 transferred. Between five and six weeks after this both the latter dogs 

 died. A careful examination of smears of the liver, spleen and bone 

 marrow failed to reveal any leishmania. All the organs were anaemic 

 and it was fairly evident that the dogs had died of profound anaemia 

 and not of kala-azar. Thus this experiment proved negative. Other 

 observations were made on the fleas themselves, and it was found 

 that fleas may be naturally infected with a flagellate closely resembling 

 the various forms of leishmania. As to what is the transmitting host 

 of this disease in Malta, all that can be said is that it is most probably 

 one of the biting arthropods which occur there. It has been suggested 

 that infection may take place through the parasites escaping from the 

 body by way of the gut. The larval fleas feed upon the faeces of the 

 adult fleas. In these faeces, which consist of partly digested blood, 

 there are passed numbers of small bodies which are very like the 

 leishmania found in kala-azar. It is these small leishmania forms 

 which produce infection when ingested by the larval flea. The 

 injection of leishmania from a case of kala-azar into a mouse was found 

 to produce a condition somewhat comparable to that arising from an 

 injection of the leishmania forms of the flea flagellate. This has 

 suggested to the author that in dealing with the parasites of the leish- 

 mania group we may have to do with an insect parasite which is just 

 adapting itself to a vertebrate host. Thus the insect in question may 

 be able to infect itself either by feeding on the blood of an infected 

 vertebrate or by eating the faeces passed by an already infected insect. 

 It is possible that the leishmania diseases are of this type and that 

 we have to do with a flagellate of an insect which naturally passes 

 from insect to insect directly, but occasionally obtains a footing in the 

 human body, producing the diseases known as kala-azar and oriental 

 •sore. 



The author states that there is apparently little evidence to warrant 

 the conclusion that a human being must necessarily be infected from 

 a dog. It is however important to prevent dogs, and also children, 

 that show symptoms pointing to kala-azar from coming into contact 

 with other dogs or children, for there is every chance, especially in 

 Malta, for the human fleas to find their way to the dogs and the dog 

 flea does occasionally attack man. The paper concludes with an 

 account of the methods of diagnosis of kala-azar and of oriental sore, 

 with some observations on the latter disease ; and the author closes 

 with the suggestion that kala-azar, whether in children or adults, in 

 all parts of the world is caused by the parasite Leishmania donorani, 

 while oriental sore is caused by L. tropica in the Old World and 

 probably also in South America, though this cannot be regarded as 

 settled. 



In answer to a remark by the President during the discussion that 

 the possibility of deriving the disease by oral ingestion had not been 

 mentioned, Dr. C. M. Wenyon stated that he had made no experiments 



