38 L. Rogers — Special Heport on Fever in Dinajpur List. [Supplt. 



districfs, for the last thirty years, and which I showed in my report 

 on the health of the neighbouring Bogra district^ also holds true of 

 that' area. In Dinajpnr there was one marked exception to this rule 

 for the rainfall was heavy in 1902, and the fever death-rate also high, 

 but on examining the monthly figures it appeared that, although the 

 total fall was high, the rains stopped earlier than usual, the amount in 

 the latter part of the rainy season being deficient. The explanation of 

 the relationship is simple enough, as when the rains are deficient and 

 especially when they are so in the latter part of the season, then the 

 time during which the country is drying up, and innumerable pools 

 suitable for the breeding of mosquitoes are present, is prolonged, and 

 the fever season, which is autumnal in these parts, begins early, and 

 also as a rule continues late, the total death-rate being considerably 

 enhanced. On the other hand, when the rains are steady and pro- 

 longed, these low-lying parts are mostly flooded and the mosquito larv89 

 are carried away. In support of this supposition I may cite the case 

 of the floods in Calcutta in 1900, during which year I was making 

 regular observations on the breeding places of anopheles in a suburb of 

 Calcutta,* and the only time I failed to find any was soon after the 

 floods. On the other hand, in high ground, such as Chota Nagpur, the 

 fever season is at the height of the rains and follows the rise and fall 

 of the ground water-level, malarial cases rapidly decreasing at the end 

 of the rains owing to the quick subsidence of the ground water-level, 

 as I showed in the case of Ranchi in 1896.^ These seasonal variations 

 are also beyond control, but a knowledge of them will not only allow the 

 variations in the incidence of malaria to be easily understood in different 

 districts, but the increases of the fever- rate may be confidently predicted 

 as soon as the character of the monsoon has fully declared itself and 

 measures taken by the medical authorities to meet the coming rise, 

 while a decrease may also be forseen on the onset of a favourable sea- 

 son, and needless alarm of a recurrence of the high fever-rate may be 

 allayed. 



Birth Rates. 



The Sanitary Commissioner has also asked for information on the 

 relationship of the birth and death-rates. In 1902 the high death-rate 

 was accompanied by a high birth-rate, that of the Dinajpur district 



i Report on the effect of the silting up of the Karatoya river on the health of 

 the Bogra district, 1901. 



2 The seasonal prevalence of anopheles and malarial fever in Lower Bengal 

 and the practical application of the mosquito theory. Journal of Hygienej October 

 1901. 



8 Indian Medical Gazette, February 1896. 



