46 



Observations Regarding Pettenkofer s Theory. 



[part I. 



of the extent of moisture present in the subsoil by the registration of the well 

 water alone ; the rainfall must also be taken into account, as the latter at Allahabad 

 appears to influence the condition of the soil more than the permanent subsoil water. 



The soil here is of a sandy, clayey nature, intermixed with layers of kunkur. 



In the hot weather extensive fissures are to be observed everywhere in the ground 

 extending to great depths, and exceedingly permeable to water. On subsequent 

 examination, it was found, when dried in the sun, to be solid to the extent of one-half, 

 the other half being interstices filled with air. 



In order to have a more precise knowledge of the extent of the porosity of the 

 soil upon which the various barracks have been built, and which are said to vary in 

 the degree of their liability to cholera, although in other respects apparently as 

 like one another as it is possible for buildings to be, and the sojourners therein subject 

 to precisely the same influences as regards food, clothing and water, it was thought 

 that perhaps some clue could be obtained by ascertaining the extent to which the 

 soil beneath the buildings was permeable to the air below. Greneral Travers, V.C., 

 immediately permitted samples of this soil to be obtained, which on my return to 

 Calcutta were subjected to the following treatment : — A little of it was reduced to 

 moderately fine powder in a mortar and placed in the sun until thoroughly dry. In 

 the meanwhile, two burettes were fixed on to a stand, the lower portion or point of one 

 being connected to that of the other by means of a piece of india-rubber tubing supplied 

 with a clip, so as to be able at will to interrupt the connection between the two tubes. A 

 given quantity of soil (100 cubic centimeters) was carefully placed in one burette, and a 

 similar amount of water in the other. The latter was allowed to flow into the former, 

 which, as it ascended in the tube containing the soil, was seen to drive out the air existing 

 in the interstices, the amount of air displaced corresponding to the amount of water which 

 entered. When the water came up to the upper edge of the soil in the tube, the 

 connection between the tubes was interrupted, and the amount of water used read off. 



As a few of the particulars of these observations may be useful for comparison 

 when more exact data shall have been obtained of the relative liability of the barracks 

 in question to cholera, I append them in a tabulated form : — 



