244 



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



at 380 feet was a layer of fresh-water shells resting on a bed of decayed wood, 

 indicating that this must at one time have constituted the surface, but that it 

 has since sunk and been covered by a soil formed by deposits from a river. 



SURFACE. 



ii [-20 feet. 



11 feet. 



i^ 15 feet. 



Fine sand 

 Loam 



Blue clay 

 Peat 



Sandy clay 



Blue clay 

 Black clay 



Diagram 10. — A Section of ground exposed in a tank at Sealdah, Calcutta [H. F. Blanpoed]. 



Taken generally, it may be stated that the more the soil of a district in 

 India approaches to the character here described, the more likely is it to be 

 one whose inhabitants are more or less constantly liable to be affected with 

 cholera. 



This general statement regarding endemic cholera is not merely applicable to 

 the districts which occupy the Gangetic plains of Lower Bengal, but also to certain 

 parts of Oudh and the North- Western Provinces, as well as to similar plains which 

 have been formed by the silt of the Godavery, the Mahanuddy, the Brahmaputra, 

 and the Cauvery — in all of which areas cholera is more or less distinctly endemic. 



We have selected certain localities of this area in which statistics have been 

 collected for a long series of years from among those sections of the population 

 regarding which care has been taken to attain fairly accurate particulars — namely, 

 the European and Native troops and the prisoners. The data which these afford, 

 although not sufficient to warrant definite conclusions as to the comparative 

 healthiness of different stations, are yet sufficient to indicate with considerable exact- 

 ness at what particular seasons of the year cholera is most prevalent. 



A glance at the map of India, facing p. 205, will show that the area over which 

 these selected stations are distributed is a very wide one, considerably larger than the 

 whole of England and Wales. As there are some districts within the limits of this 

 area considerably less prone to the disease than others, so are there districts in the 

 Bengal Presidency beyond them in the larger towns of which cholera may also 

 be said to be endemic, as for example Fyzabad and other towns in Oudh. 



