New YorK AGRICULTURAL EXPERIMENT STATION. 207 
one kind of cytolytic enzym is present, which is allied to 
pectinase but diifers from it in that it acts primarily on hemi- 
cellulose and to a less degree on the pectic elements. The sec- 
ond is that two distinct cytolytic enzyms are present in mix- 
ture, viz.,. a small amount of pectinase, which causes 1{ e 
hydrolysis of the pecti¢ elements, and a relatively larger 
amount of another enzym which acts on the hemicelluloses. 
Newcombe’s results, referred to earlier in this paper, strongly 
favor the second of these two possible explanations and ex- 
clude the first. 
Accepting the conclusion that there is an enzym other than 
pectinase in taka-diastase, barley, malt, etc., of which the 
hydrolytic action is chiefly or wholly on the hemicellulose ele- 
ments of the cell membrane, we need a distinctive name for 
that also. The one introduced by Oppenheimer (1901 : 187), 
cellulase, seems fit except that it is too general. It implies an 
activity on the celluloses generally, and especially on the cellu- 
loses proper. This enzym, which acts only on the hemicellu- 
lose, may better be termed hemicellulase. This is a self-ex- 
planatory name and leaves the name cellulase to be appled 
either in a more general sense to all cellulose enzyms, includ- 
ing this hemicellulase, or, as would be preferable in our 
Opinion, reserving it for application to the enzyms which 
hydrolyze the celluloses proper, as recently studied by Ome- 
lianski (1902). - These terms, pectinase and cellulase, have 
heretofore been used rather vaguely as synonyms. of Grtiss’ 
term cytase, i. e., as applicable to cytohydrolysts generally. If 
they be restricted to the more exact usage defined above, it 
leaves the words cytohydrolyst, or better cytolyst, and cytase 
as convenient and satisfactory terms for use in the broader 
sense to include in a general or indefinite way both of the 
above, and indeed any other related’enzyms capable of hydro- 
lyzing the cell membranes, 
