1884 .] Correspondence. 243 
water by the addition of a few drops of a solution of aluminium 
sulphate. On straining off and re-dissolving the precipitate the 
badteria are found. The success of this process, known as 
Brautlecht’s method, shows that disease-germs need not be 
feared in the effluent water of sewage which has been treated 
with sulphate of alumina. Had this fadt, and the adtion of alum 
in rendering foul waters harmless, — well known in China, Cochin 
China, &c., — been considered, the public might have been spared 
the rechauffee of the Report of the Rivers’ Pollution Commis- 
sioners to which they were treated by Dr. Frankland. 
Argus. 
Erratum. — March No , heading of article on “Vaccination,” 
for Gilebs read Gibbs. 
