1867.] 



The Public Health. 



71 



a reservoir, and runs for a couple of miles by the side of the 

 Hackney Cut, down to its other reservoir north of Bow, and near 

 the Lea. The present Cholera field derives its waters from these 

 works." From the date this was written up to the termination of 

 the epidemic, accumulated evidence has all pointed to this one con- 

 clusion, that the water-supply of the district was the exciting cause 

 of this awful visitation of Cholera. 



At the same time, it should be remembered that up to the pre- 

 sent moment no chemical or physical means exist by which the 

 presence of Cholera poison, or any substance having a tendency to 

 give Cholera, can be detected. No sooner had the Cholera appeared 

 at the East End, than attention was directed to the chemical com- 

 position of the water. Dr. Frankland, of the Eoyal College of 

 Chemistry, who gives a monthly analysis of the principal waters 

 supplied to London, in the Kegistrar-Greneral's Reports, had pub- 

 lished an analysis of the water of the East London Company on 

 the 1st of July, and after the Cholera had broken out, he again 

 analysed the water on the 1st of August. We give the result of 

 the two analyses : — 



East London Company's 

 Water. 



Solid Matter in 

 100,000 fest. 



Organic Matter 

 in 100,000 feet 



Oxygen 



required to 



Oxydize again 



with. 



Degree of 

 Hardness. 



Collected 1st of July, \ 

 1866 J 



Collected 1st of August, \ 

 1866 / 



24-38 

 26-14 



1-94 

 1-44 



•0344 

 •0328 



16-0 

 17-7 



This analysis shows that, although the water contained less organic 

 matter in August than in July, that nevertheless in July the water 

 could not be regarded as unfit for drinking purposes. It has been 

 sometimes supposed that water contaminated with a certain amount 

 of organic matter, when taken by healthy persons, will engender a 

 condition of the system in which the poison of Cholera conveyed 

 through the air, will produce that disease. During the late epi- 

 demic of Cholera in London there has been nothing to support this 

 theory. In many districts of London the surface well-pumps 

 remain open, and are, indeed, in certain spots the only source of 

 the supply of water in the neighbourhood in which they exist. 

 The water of these pumps has been again and again shown to con- 

 tain organic matter varying from 5 to 40 grains in the gallon, and 

 yet Cholera has not occurred as the result of their use. In all 

 cases where the pump has been shown to be the cause of disease, 

 then it has been either demonstrated that the well has communi- 



