1918] 
BONNS—ETHERIZATION AND ENZYME ACTIVITY 275 
ized tissues and controls that have been noted in the case of 
dextrin. 
The conclusion seems unavoidable, in the light of the results 
above noted, that for a study of the effect of etherization upon 
carbohydrates a method must be employed that obviates the 
various undesirable factors involved in the processes of 
enzyme extraction. Such extraction and the filtration of 
dense colloidal plant solutions involve long periods of time 
which are undoubtedly unfavorable to enzyme isolation. 
There is the added objection, also apparent in the foregoing 
table, that there is no means of concluding, in the absence of 
positive results, whether the enzyme is not present in the 
tissues or is not amenable to extraction by the method used. 
Additional data on carbohydrate enzymes with respect to their 
action following etherization have been obtained in a supple- 
mentary series of experiments in which the foregoing diffi- 
culties have been eliminated; the results of this series will 
be discussed later. 
The titration of 10-сс. portions of the substrates of ethyl 
acetate, ethyl butyrate, and oil emulsion, with sodium hydrate 
showed total absence of lipolytic activity. This was not un- 
expected, for several reasons. In the first place, experiments 
showing lipase action have in the past been made for the most 
part with material of high fat or oil content, such as seeds, 
especially those of Ricinus, rather than with storage organs 
in which the carbohydrates predominate, such as corms, bulbs, 
and tubers. Experience has shown that in general, under the 
most favorable conditions, the amount of active enzyme prep- 
aration extracted from plant tissues is quite small in propor- 
tion to the amount of material used. The most notable excep- 
tion in this respect is doubtless the urease derived from sev- 
eral members of the bean family. The chances of obtaining 
an active lipase preparation from organs such as those used 
in the present study, even with the most favorable prepara- 
tion methods, were therefore small. 
In the second place, most lipases, as pointed out by Euler 
(712), are insoluble in water. Berezeller (711) concluded that 
lipase of the panereas does not go into solution and that the 
