254 



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



case of Calcutta, however, no close connection can be detected between the less marked 

 variations in the cholera-prevalence and water-level. 



As the level of the water in the group of stations under consideration is dependent 

 on the local rainfall, it is not considered necessary to refer to the influence of rainfall 

 specially, as the remarks made regarding this factor in the history of cholera-prevalence 

 when speaking of Calcutta apply equally here. It may, however, be mentioned that in 

 some of these stations, especially at Dum-Dum, it has been ascertained that no relation 

 exists between the height of the river and the level of the water in the well. 



(b) The stations of Purneah and Berhampore. 



In order to illustrate still further the relation of cholera prevalence to physical 

 conditions in the endemic area, we select three other stations — Purneah, Berham'pore 

 and Dinapore. The cholera history of the first two extends over a period of twenty-three 

 years, and regarding the last, records exist extending over more than half a century. The 

 following table gives the monthly prevalence of the disease during the above periods, and 

 also the average monthly rainfall and fluctuation of the water-level : 



TABLE XLVIII. 



A Monthly Statement of the cases of Cholera that have been registered among 

 Prisoners at Purneah ; and among European and Native Troops and 

 Prisoners at Berhampore and Dinapore; also the average Rainfall and 

 Water-level. 



