xxiv Annual Address. [February, 1917. 



find no differentiating point from malaria, I therefore visited 

 Svlhet to the south of the Khasia Hills, where kala-azar was then 



unknow 



x 



ia which in 



every respect, including investigations of the blood changes 

 resembled kala-azar of the Brahmaputra Valley, except that 

 they were much more chronic, and sometimes lasted as many 

 years as epidemic kala-azar did months. The next picture 

 shows two such chronic cases in Svlhet. With the boldness of 

 comparative youth I therefore declared the spreading kala-azar 

 of Assam to be an epidemic infectious form of malaria, corres- 

 ponding in some respects to the well-known Mauritius malarial 

 epidemic in 1877. We shall see presently that I was partly 

 wrong and partly right in coming to this conclusion. 



The Prevention of the Spread of Kala-Azar. 



However, I was not content with merelv theoretical con- 

 siderations, but strove for practical results from my inquiries 

 and I early realized the great practical importance of finding 

 out as much as possible regarding the spread of the disease in 

 order to obtain a basis for preventative una si ires. Among 

 other things I learned that the Garos after bitter experience 

 hit upon the plan of evacuating infected villages and moving 

 to new sites, apparently with good results. I therefore sought 

 for more accurate data on the tea gardens which had become 

 badly infected in the Nowgong district, and on which I investi- 

 gated many cases with the help of my friend \)v. Doddfl Price, 

 who has a unique experience of kala-azar, and has rendered me 

 the greatest possible assistance throughout a number of years. 

 I ascertained that on one of his gardens so main- deaths had 

 occurred from kala-azar that 200 new coolies had to be imported 

 at one time. He had already independently recognized the in- 

 fectiousness of the disease before I went to Assam, and baa 

 arranged for separate cooly lines to be built to prevent as many 

 as possible of the new coolies going into the infected houses of 

 the old lines. Only 150 could be accommodated in the nt>* 

 lines so fifty had to go into the old one On learning this I 

 at once set to work to ascertain the results of this importan 

 measure, and we found that in the course of two years no 

 single case of kala-azar had occurred in the new lines' (and the 



same was true eighteen years later), while no less than 16 per 

 cent of the new coolies firing in the old infected lines were 

 already dead of the disease, although the two sites were only 

 about two hundred yards apart. This experience led me t 

 urge moving out all the health v people from the infected line 

 into new ones, taking none from infected houses, segregating ™e 

 remaining infected families and destroying the old houses. 

 The results were so sucet rful that the plan was repeated I >) 

 Ur Dodrls Price on other gardens, and in 1913 during a visit 

 to Assam in the Pnja vacation we worked oui ihe results ot 



