DESTRUCTION OF BACTERIA BY CHEMICALS. 155 
Pieces of sterile thread (one inch) were placed 
in bouillon cultures of anthrax and typhoid bacilli 
for ten minutes, then removed to Petri dishes, and 
dried in the incubator for twenty-four hours. These 
were then placed in serum and bouillon respectively 
(2.5 ¢.c.). From each a control was taken. Then 2.5 
e.c. HgCl, (1: 1000) and carbolie solution (5 per cent.) 
was added to either, as shown in A, B, C, and D. 
From each one thread was taken at varying periods of 
time and planted in bouillon tubes. The threads from 
A and B (HgCl, solution) were washed in sterile water, 
then in a solution of ammonium sulphide (25 per cent.), 
then in sterile water again, then in the bouillon. The 
threads from the carbolic solution were washed in sterile 
water before planting. 
Observations: The serum seems to have an inhibi- 
tory action with the bichloride solution, allowing a 
growth up to forty-five minutes, while with bouillon 
the action is much quicker, preventing a growth after 
an exposure of one minute or over. With the carbolic 
acid solution the serum seems to have made little or no 
difference in the results. 
Many substances which are strong disinfectants be- 
come altered under the conditions in which they are 
used, so that they lose a portion or all of their germ- 
icidal properties; thus, quicklime and milk of lime are 
disinfecting agents only so long as sufficient calcium 
hydroxide is present. If this is changed by the carbon 
dioxide of the air into carbonate of lime it becomes 
harmless. Bichloride of mercury and many other 
chemicals form compounds with many organic and 
inorganic substances, which, though still germicidal, 
are much less so than the original substances. 
