158 REPORT OF DEPARTMENT OF BACTERIOLOGY OF THE 
precipitate was dried immediately after washing with 95% 
alcohol. The balance was immersed for nineteen hours in 
absolute alcohol, then for forty-eight hours in chloroform,® 
changing the chloroform once during this pediod. Upon its 
removal from this fluid the precipitate quickly dried to a 
chalky, brittle, white mass. Comparative trials, using 5% 
aqueous solutions of the precipitate dried from the 95% alco- 
hol and that where the chloroform was used, showed them 
to be equally active. These results established our confidence 
in the method of drying directly from 95% alcohol and we 
have therefore continued so to do as it is more economical 
of both chemicals and time. We would again say, however; 
that its most suecessful use is in our judgment conditioned 
upon quick drying secured by breaking up the moist pre- 
cipitate and placing it in a current of dry, warm air. Inas- 
much as we found the use of ether injurious to the enzym 
and van Hall (1903) says that chloroform destroyed it in 
his trials, it is at least incumbent on anyone who employs 
either of them to determine their safety. It is, of course, 
possible that even with the same enzym secured from different 
broths and in mixture with different compounds there might 
be different results with the same chloroform or ether, and 
even more likely that some brands of ether or chloroform 
might carry in solution substances acting deleteriously upon 
So sensitive a compound as these enzyms. 
2. The most favorable strength of alcohol.—Precipitation 
with various percents of alcohol was tried early in the work 
to determine the relative amounts and strengths of the pre- 
cipitates thus secured. 
In the first trial, using beef broth cultures five days old 
and increasing the alcohol at four steps, fractional precipi- 
tates were secured as follows: 
At alcoholic strength of 20%, a mere trace of precipitate 
was secured. 
At alcoholic strength of 40%, secured 15% of total pre- 
cipitate. 

5 Mallinekbrodt’s ‘‘ M.C.W.” brand. 
