ACTION OF ACIDS AND ALKALIES. 181 
gramme of SO, added to two thousand of bouillon prevents the de- 
velopment of putrefactive bacteria and after a time destroys the 
vitality of these bacteria. The writer found that pus cocci failed to 
grow in a culture solution containing one part of SO, in five thousand 
of water. 
Nitric Acid, HNO,.—In the writer’s experiments an eight-per- 
cent solution which contained 0.819 gramme of HNO, in each cubic 
centimetre sterilized broken-down beef tea containing spores, and 
five per cent failed todo so. Kitasato, inexperiments upon the chol- 
era spirillum and typhoid bacillus, obtained results corresponding 
with those obtained with hydrochloric acid—0.2 per cent destroyed 
vitality at the end of four or five hours. In these experiments the 
acid used contained 0.35 gramme HNO, in one cubic centimetre. 
Nitrous Acid.—In the writer’s experiments on vaccine virus (1880) 
exposure for six hours in an atmosphere containing one per cent of 
nitrous acid destroyed the virulence of dried virus upon ivory points. 
Hydrochloric Acid, HCl.—Anthrax spores are destroyed in ten 
days by a two-per-cent solution, but not in five days (Koch). Tested 
upon broken-down beef tea containing spores of Bacillus subtilis, it 
was effective in two hours in the proportion of fifteen per cent, but 
failed in ten per cent (Sternberg). In the experiments of Kitasato this 
acid destroyed the typhoid bacillus in five hours in the proportion of 
0.2 per cent, and the cholera spirillum in 0.132 per cent—the acid 
used contained 0.26 gramme HCl in one cubic centimetre. We give 
the more recent determinations of Boer in tabular form. Its germi- 
cidal power was tested upon bouillon cultures which had been kept 
for twenty-four hours in an incubating oven ; time of exposure to 
the action of the acid solution, two hours. 
Restrains Destroys 
development. vitality. 
Anthrax Dacilusieii cies eevee a's sesesne o¥ es 1:3400 1:1100 
Diphtheria bacillus....... 2... eee e eee eee eens 1:3400 1:700 
Glanders bacillus..........0ceee veces eeveeeces 1:700 1:200 
Typhoid bacillus si. s60 cacsaevrneseeeseeees 1: 2100 1:300 
Cholera spirillum ..........02 02 eee cent cece 1 : 5500 1: 1350 
Chromic Acid.—In Koch’s experiments a one-per-cent solution 
destroyed anthrax spores in from one to two days. In the propor- 
tion of 1:5,000 it prevents the development of putrefactive bacteria 
(Miquel). 
Osmic Acid.—A solution of one per cent kills anthrax spores in 
twenty-four hours (Koch). It is an antiseptic in the proportion of 
1:6,666 (Miquel). 
Phosphoric Acid.—Exposure for four or five hours to a solution 
