160 Report oF DEPARTMENT OF BACTERIOLOGY OF THE 
twenty-four hours on ice and was then filtered through six 
tnches of calcined sand. This cleared it up but slightly. 
Sufficient alcohol to make this an 80% solution was added 
and the precipitate collected and dried. Comparisons were 
then made between like solutions of this reprecipitate, of that 
passed through the porcelain filter, and of the original. That 
passed through the filter was scarcely equal to the original 
in strength; that passed through the sand was slightly 
stronger, but not enough so to be of practical consequence. 
Reprecipitation was therefore considered of little advantage 
and was not tried further. 
4, The relation of strength of solution to activity—When 
this dried alcoholic precipitate is added to water it swells 
promptly, but apparently only a small fraction of it is dis- 
solved. Two questions arose early in our work; first, as to 
the relation of the strength of this solution to the activity of 
the enzym; second, as to the relative enzymic activity of (a) 
such solutions of the precipitated enzym and (b) of the original 
broth cultures from which the precipitates were secured. 
To determine the first point amounts equal to 1%, 5% and 
10% respectively were added to distilled water, plus chloro- 
form, and their relative activities compared on carrot and 
turnip root sections. The results in all cases showed the 
activity to increase with strength of solution, but not pro- 
portionately. The average of several trials led to the con- 
clusion that, with the precipitate used, it required twenty-five 
minutes in the 1% solution to secure as complete enzymic 
action as was secured in fifteen minutes in the 5% solution 
and in ten minutes in the 10% solution; that is to say, the 
relative activities of the 1%, 5% and 10% solutions stand 
in the ratio of 6, 10 and 15, 
Our practice in all of the work here reported with alco- 
holic precipitates has been to use 5% solutions unless other- 
wise stated. ; 
The second question is of quite as great interest, since it 
involves the query as to whether the enzym is or is not injured 
by the action of the alcohol. 
