February, 1917. J Annual Address. xxvii 



ship last year, although it is but a small recognition of such 

 an important discovery. The way was now cleared for more 

 rapid advance, and Dr. Bentley and myself independently 

 found the same parasite in epidemic kala-azar in Assam, and 

 1 also found them in cases in the north-west of the Dinajpur 

 district, where the disease had been known as kala-dukh. 

 Thanks to the kindness of the Physicians of the Medical College 

 Hospital in 1904-05, and especially to Surgeon-General Harris. 

 I was able to investigate scores of cases of what had hitherto 

 been always regarded as malarial cachexia, with the result ot 

 show ing that a large proportion of them were kala-azar. These 

 i 1 nervations established the important fact that a sporadic- 

 form of kala-azar is widely prevalent in Lower Bengal, which 1 

 found to be exactlv similar to the cases I had formerly studied 

 in Sylhet, of which I have shown you a photo. The mysten 

 of the nature of kala-azar was thus cleared up. the destructive 

 Brahmaputra Valley wave having been an epidemic form of the 

 disease which is endemic in Lower Bengal and Sylhet; so that 

 although I was wrong in regarding it as malarial, 1 was correct 

 in saving it Mas an epidemic variety of the disease I found in 

 Sylhet, which had always been regarded as malarial cachexia, 

 but which we now know to be sporadic kala-azar. As special 

 skill and laboratory facilities are required for demonstrating 

 the parasite of kala-azar, while the treatment of the disease is 

 different from that of chronic malaria, it still remained a matter 

 of great practical importance to solve the century-old problem 

 of finding a simple clinical differentiation between kala-azar 

 and malarial cachexia. Only last month I recorded the results 

 of three years' investigation of this problem in the Medical 

 College Hospital, thanks to facilities kindly afforded me by ray 

 medical colleagues, which has, I believe, resulted in a simple 

 and practical solution of this difficulty, which will enable th< 

 curative treatment I shall come to presently, being successfully 

 used by the general practitioner even in places remote from 



laboratories. . 



The discoverv of the parasite of kala-azar in HMM placed 

 us in a position to studv it with a view to ascertaining its life- 

 history,' and so to obtain a clue to the mode of infection. In 

 the following year I was fortunate enough to succeed in culti- 

 vating this protozooal parasite in test tubes under certain con - 

 ditions and in watching the minute spleen form develop int.. 

 a long flagellate organism resembling one of the stages of a 

 trvpanosome. but which further study showed to belong to the 

 closelv allied herpetomonas. The next picture illustrates the 

 stages of the development. This discovery gave the required 

 clue to the nature and probably life-history of the par. ite, a- 

 similar organisms are found naturally in the digestive canals of 

 certain flies, indicating that the infection is probably insect 

 borne T spent the next vear in studying the conditions f ;1 V our 



