for the years 1917-20. vii 



and myself to the southern end of the Chilka Lake in the extreme north- 

 east of Madras. 



The first half of April, 1920, was occupied by Major Sewell, who 

 had just rejoined the post of Surgeon- Naturalist from military duty, 

 and myself in making a survey of the aquatic molluscs of certain parts 

 of the Nilgiri plateau. Major Sewell also spent a fortnight in July 

 in Bombay and certain places in the Western Ghats between that city 

 and Poona, and travelled for about three weeks in October in the eastern 

 part of the Nilgiri plateau and the adjacent Wynaad, tracing the dis- 

 tribution of the molluscs and their parasites downwards and westwards 

 to the narrow plain between the Ghats and the sea. 



These extensive tours could not be paid for from the ordinary 

 budget of the department and a special grant of Rs, 6,000 was made for 

 the purpose from the Indian Medical Research Fund in 1918. In 1920 

 an additional grant of Rs. 7.000 was made by the Education Depart- 

 ment of the Imperial Government, partly to cover special expenses of 

 the Seistan tour and partly for the salary of Major R. B. Seymour Sewell, 

 I.M.S., while acting as Superintendent. In the course of our travels 

 we were indebted for assistance to a large number of officials belong- 

 ing to different dej^artments. I may specially mention the names of Dr. 

 A. Lankester, head of the medical department in Hyderabad, Captain 

 A. J. Powell, R.A.M.C., who was stationed in Secunderabad, Sir Frederick 

 Nicholson, K.C.S.I., at the time Honorary Director of Fisheries in 

 Madras, Mr. Sundara Raj of the same dejDartment, who was deputed 

 to accompany me on my tour in Madras, Mr. B. J. Gould, I.C.S., and 

 Major D. Heron, CLE., I. M.S., respectively British Consul and British 

 Vice-Consul in Seistan, and Captain C. H. Donald, Warden of 

 Fisheries in the Punjab, who accompanied me in that province. 



As a result of the tours briefly sketched and of investigations under- 

 taken in the field we were soon able to assure the sanitary authorities 

 that, so far as we could see, there was little danger of the spread of 

 Schistosomum licematohium, which was chiefly apprehended, in several 

 of the more important military cantonments in India. In some, 

 for diverse reasons, aquatic molluscs were practically absent, while in 

 others there was little risk of men coming in contact with the parasite. 

 Our results so far as this particular parasite was concerned were purely 

 negative, but even so — or rather all the more so — we may claim that 

 they saved the expenditure of large sums of money on precautions 

 which would have been completely useless under Indian conditions 

 and might have led to much inconvenience, and this without the slight- 

 est transgression on our part beyond the limits of pure biology. 



We have been obliged to leave Sind out of consideration in our 

 survey because the Government of Bombay wished to do the work 

 themselves without assistance in the field from Imperial ofiicers. 



I would strongly urge the importance of extending the survey of 

 the aquatic molluscs and their parasites throughout Burma and Assam, 

 where certain trematodes are known to be endemic in man ; but with 

 the staff and funds at my disposal it is impossible for me to arrange 

 for comprehensive field work in countries in which travelling is so slow 



