JOURNAL 



OF THE 



ASIATIC SOCIETY OF BENGAL 



Vol. LX1X. Part II. — NATURAL SCIENCE. 

 No. IV.— 1900. 



XVII. — The relationship of the water-supply, water-logging, and the 

 distribution of Anopheles Mosquitos respectively, to the prevalence 

 of Malaria north of Calcutta. — By Leonard Sogers, M.D., M.R.O.P., 

 I.M.S., Professor of Pathology, Medical College. 



[ With a Map. ] 



£ Received and read 4th July, 190O. ] 



The tract of country in which the present inquiry was carried out 

 extends along the East bank of the Hooghly river from Calcutta to 

 Naihati, a distance of 25 miles. The area is fairly typical of Lower 

 Bengal, and has for a long time been looked on as water-logged and very 

 malarious. In 1889 Dr. Gregg, then Sanitary Commissioner of Bengal, 

 after a careful inspection, came to the conclusion that the unheal thiness 

 was due to certain drainage channels having been silted up, and a scheme 

 for re-excavating some of them was prepared, but has not yet been carried 

 out. Owing to an unusual prevalence of fever in 1899 a further inquiry 

 into the health of the tract was ordered, and was carried out by me in 

 February last. 



The plan of the enquiry was as follows. As the essential point 

 to be determined was the proportion of the inhabitants of the various 

 parts of the area who were suffering from malaria, a large number of 

 persons were examined for enlargement of the spleen; its size being 

 noted as either just felt, two fingers breadth below the ribs, four 

 fingers breadth below, or extending beyond the navel. The spleen- 

 count as a test for the degree of malaria in a tract of country was 

 J. II. 60 



