47 
The results are as follows: 
Name of ester. 
Cubic centime- 
ters N / 10 sodi- 
um hydroxide 
required. 
Per cent of 
hydrolysis. 
Ethyl acetate 
0. 05 
1.00 
Ethyl propionate 
.60 
12.00 
Ethyl butyrate 
1.10 
22.00 
In a second series of experiments with the ethyl esters, in which the 
lipase was allowed to act for two hours, the other conditions being the 
same as those given above, the following numbers were obtained: 
Name of ester. 
Cubic centime- 
ters N 10 sodi- 
um hydroxide 
required. 
Per cent of 
hydrolysis. 
Ethyl acetate 
0.45 
9. 00 
Ethyl propionate 
1. 70 
34. 00 
Ethyl butyrate 
2. 80 
56. 00 
and ethyl esters of 
these acids, the general trend of the results is the same, and that the 
same relation holds for the two series of ethereal salts. It is also evi- 
dent from these results that unlike the alkyl radical, the acid radical 
in an homologous series of ethereal salts exerts a great influence on 
their hydrolysis by lipase. It will be seen that the amount of pro- 
pionate hydrolyzed in a given time by lipase is almost an exact mean 
between the several amounts of acetate and butyrate h} T drolyzed during 
the same interval under the same conditions of temperature, etc. In 
view of the chemical relation existing between these three substances 
this is an interesting fact, and tends to confirm the earlier results 
obtained b} T Loevenhart and myself with pancreatic lipase. 
Some determinations have also been made of the rate of hydrolysis 
of methyl and ethyl formates as compared with the corresponding 
acetates under the following conditions: Four solutions were prepared 
containing 50 cc. of N TOO methyl and ethyl formate and methyl and 
ethyl acetate, respectively. To each of these 5 cc. of a clear solution 
of lipase was added. They were then allowed to stand at ordinary 
temperature for one hour, at the end of which time the} T were titrated 
with N 10 sodium hydr oxide with the following results: 
It will be observed that both with the method 
Name of ester. 
Methyl formate 
Ethyl formate . 
Methyl acetate 
Ethyl acetate . . 
Cubic centime- 
ters of N/10 so- 
dium hydrox- 
ide required. 
Per cent of 
hydrolysis. 
0. 80 
16.0 
.87 
17.4 
.60 
12.0 
. 65 
13.0 
