248 



Cholera m Relation to Certain Physical Phenomena. [part i. 



we find that the dozen stations which form the group under consideration have 

 during the last 20 to 50 years furnished 15,699 cases of cholera,* the monthly 

 distribution of which is as follows : 



TABLE XLIV. 



Showing the Monthly ^prevalence of Cholera among Soldiers, Sepoys and Prisoners in 

 twelve stations in Lower Bengal during varying periods up to 51 years. 



In the second and third chapters (of I. pp. 216-242) we have entered with some 

 fulness into the question of the relation which cholera prevalence holds with regard to 

 the pressure, temperature and humidity of the atmosphere in Calcutta, and the remarks 

 there made apply, with more or less force, to this group of stations ; for the meteorology 

 of the different places manifests a close resemblance,5 and data are not available to enable 

 any but general comparisons to be made. 



With regard to the conclusion arrived at, that the minimum of cholera agreed 

 with low pressure, it will be noted that this takes place during the heavy rainfall of 

 the wet season, so that for this and other reasons, as already intimated, it may be 

 inferred that the influence exerted on the prevalence of the disease, if any, by 

 atmospheric pressure, must probably be of an indirect character. 



The coincidence of the maximum rainfall with the minimum cholera-prevalence is 

 nearly as evident in most of the stations of this group as it was in Calcutta. This is 

 evident whether the stations be studied individually (as may readily be done by the 

 aid of Table XLIII.) or be studied as a group. This point will be more fully discussed 

 further on. 



(c) Prevalence of Cholera according to Seasons in Endemic Area : also the Rainfall. 



As might be supposed, no satisfactory comparison can be instituted between data 

 of monthly prevalence of cholera in communities of very different strengths by a mere 

 tabulation of monthly results or even by a comparison of monthly ratios. Satisfactory 

 comparisons may, however, be made by taking the seasonal ratios of the total number 

 of cases which have occurred in individual stations. Such ratios are shown in the 

 following table (XLV), together with the relation which exists between cholera and 

 rainfall in Lower Bengal when studied by seasons, t 



* Occasionally reconis of deaths only could be obtained. 



f Whilst preparing these seasonal tables of rainfall, Mr. H. F. Blanford very kindly favoured us with a 

 Kianuscript copy of his table of monthly rainfall, which is to appear in the forthcoming Report on the 

 Meteorology of India, so that the figures represent the lH,te3t data available. 



