the flask originally containing it. and the clear lipase solution had 
altered considerably in appearance. It now contained quite a percep- 
tible coagulum. whereas that in the flask containing air still remained 
clear. The lipolytic activity of the two solutions was then tested by 
adding to each 10 cc. of a X 20 solution of ethyl butyrate: 10 cc. of 
such a solution, if completely hydrolyzed, would require 5 cc. of X 10 
sodium hydroxide to neutralize the butyric acid formed. A drop of 
an alcoholic solution of phenolphthalein was also added to each flask, 
and the free acid in each neutralized with X 10 sodium hydroxide. 
The two flasks were then allowed to stand at ordinary temperature, 
and the amount of hydrolysis in each determined from time to time 
bv means of X 10 sodium hydroxide, with the following results: 
Cubic centimeters 
X 10 sodium hr- 
Per cent of hydrol- 
ysis. 
Time. 
dxoxide required. 
Xo. 1. 
of 
o 
'A 
Xo. 1. 
Xo. 2. 
4 hour 
yone. 
0.45 
0 
9 
1 hour 
Xone. 
.45 
0 
9 
2 hours 
Xone. 
.90 
0 
18 
24 hours 
0. 10 
3.30 
2 
66 
Total 
.10 
5. 10 
2 
102 
It is evident, therefore, from these results that a solution of clear 
lipase, 5 cc. of which can ordinarily hydrolyze 0.058 gram of ethyl 
butvrate in twentv-four hours, under the conditions given in the above 
will, after it has been acted upon by 0.312 milligram of ozone, hydro- 
lyze only 0.00116 gram of ethvl butvrate. 
A second lot of ozonized oxygen was prepared, 50 cc. of which was 
found to liberate an amount of iodine equivalent to 2.2 cc. X’ 50 sodium 
thiosulphate. From this it follows that the gas contains 1.009 milli- 
grams of ozone in 50 cc. In order to test the toxicitv of ozone of this 
concentration to lipase. 5 cc. of a clear lipase solution were introduced 
into a glass-stoppered flask. Xo. 1. containing this amount of ozone, 
and 5 cc. of the lipase solution into a flask of the same capacity, Xo. 2, 
filled with air. The two flasks were allowed to stand in a dark closet 
forty minutes, at ordinary temperature. After exposure to the ozone 
for this interval, the lipase solution, which was perfectly clear and 
transparent originally, was found to have become cloudy and more 
or less opaque, and the odor of ozone had largely disappeared from the 
flask. Ten cc. of a X 20 solution of ethyl butyrate were then added 
to each flask, also a drop of phenolphthalein. and the solutions ren- 
dered neutral by means of X 10 sodium hydroxide. The flasks were 
then allowed to stand at ordinary temperature and the amount of 
