45 
The hydrolysis of ethyl, normal butyl, and iso-butyl acetates by 
lipase has been determined under the following conditions: 10 cc. of 
the N/40 solutions of these esters were brought together with 5 cc. of 
a clear solution of liver lipase. One set of experiments was allowed 
to stand for one hour, the other for four hours, when they were 
titrated with N/50 sodium hydroxide, with the following results: 
Table 2. 
No. of 
series. 
No. of 
experi- 
ment. 
Name of ester. 
Time. 
Cubic centi- 
meters N/50 
sodium hy- 
droxide re- 
quired. 
Per cent of 
hydrolysis. 
( 19 
Ethyl acetate 
1 hour 
0. 60 
4. 8 
8 
\ 20 
Butyl acetate 
do 
.50 
4.0 
21 
Iso-butyl acetate 
do 
.55 
4.4 
f 22 
Ethyl acetate 
4 hours 
1. 10 
8. 8 
9 
| 23 
Butyl acetate 
do 
.80 
6.4 
1 24 
Iso-butyl acetate 
do 
.80 
6.4 
These results furnish us with the following coefficients whereby to 
express the effect of the several alk}d radicals on the lipolytic hydrol- 
ysis of ethereal salts in terms of the methyl and ethyl radicals as unity. 
Name of radical. 
Ethyl, from experiments . . . 
Mean ... 
Allyl, from experiments 
Benzyl, from experiments . . 
Butyl, from experiments 
Iso-butyl, from experiments 
Lipolytic coeffi- 
cients in terms 
of methyl as 
unity. 
1 and 2 
1.08 
3 and 4 
1.2 
5 and 6 
.8 
8 and 9 
1.06 
11 and 12 
1.225 
13 and 14 
1.18 
15 and 16 
1.18 
17 and 18 
1.28 
1.128 
5 and 7 
1. 10 
8 and 10 
1.17 
In terms of 
ethyl as unity. 
19 and 20 
.84 
22 and 23 
.73 
19 and 21 
.91 
22 and 24 
.73 
These numbers indicate that the alkyls, methyl, ethyl, butyl, isobu- 
tyl, allyl, and benzyl exert very nearly the same influence on the 
hydrolysis of an ethereal salt by lipase; the greatest difference observ- 
able being an increase of ethyl over methyl of 0.28, in terms of 
methyl as unity, and a decrease of butyl and iso -butyl as compared 
with ethyl of about one-fourth, in terms of ethyl as unity. The fact 
that butyl and iso-butyl acetate are hydrolyzed to practically the same 
