hydrolysis determined from time to time by means of X 10 sodium 
hydroxide solution, with the following- results: 
* 7 C) 
Time. 
Cubic centimeters 
X 10 sodium hy- 
droxide required. 
Per cent of hydrol- 
ysis. 
Xo. 1. 
Xo. 2. 
Xo. 1. 
Xo. 2. 
1 hour 
None. 
1.00 
0 
20 
1 hour and 10 minutes 
None. 
1.50 
0 
30 
4 hours and 15 minutes 
0. 05 
*5 2.50 
1 
50 
Total ~ 
0. 05 
5.00 
1 
100 
It is evident, therefore, from these results that an amount of lipase 
capable of hydrolyzing 0.0580 gram of ethyl butyrate in five hours 
and fifty-live minutes is practically destroyed when exposed to the 
action of 1.009 milligrams of ozone for forty minutes. 
COMPARISON OF OTHER OXIDIZING AGENTS AND ANTISEPTICS WITH 
OZONE. 
In the light of these results, it seemed of interest to compare various 
other oxidizing agents and antiseptics with ozone with regard to their 
toxicity to lipase. Thus far 16 substances have been tested. These 
are: Chlorine, bromine, iodic acid, chromic acid, perosmic acid, suc- 
cinic peroxide acid, hydrocyanic acid, iodine cyanide, sodium fluoride, 
formic aldehyde, .t-rikresol,® silver nitrate, copper sulphate, mercuric 
chloride, potassium permanganate, and potassium nitrite. 
Solutions of these several substances were prepared of such con- 
centration that 1 cc. of a given solution contained a quantity of the 
substance equivalent to 0.312 milligram of ozone, or with such of these 
as are oxidizing agents, 1 cc. of a given solution contained a quantity 
of the substance capable of furnishing an amount of oxygen equiva- 
lent to the active oxygen in 0.312 milligram of ozone. 
In order to test the toxicity of these several substances to lipase, 1 
cc. of the solution of the substance was added to a clear solution of 
liver lipase of the hog and the mixture allowed to stand at ordinary 
temperature twenty-four hours; 10 cc. of X 20 ethyl butyrate were 
then added and the mixture again allowed to stand in the dark for 
twenty-four hours. The acid resulting from the hydrolysis of the 
ethyl butyrate by lipase was then titrated with X 10 sodium hydroxide. 
The normal lipolytic power of the lipase solution employed in this 
series of experiments was determined in the following manner: 1 cc. of 
water was added to 5 cc. of the lipase solution and the mixture allowed 
to stand twenty-four hours at ordinary temperature in the dark; 10 cc. 
a Trikresol is the trade name of a mixture of the three cresols. 
