262 Vines. — Proteolytic Enzymes in Plants. 
Amongst the plants that I have examined, there are only 
two, the Melon and the Mushroom, that contain enzymes 
which approach those just mentioned in their power of 
peptonization and proteolysis. Whilst all the others readily 
proteolysed Witte-peptone, their action on the higher pro- 
teids, so far as it was tested, was relatively feeble and in some 
cases altogether wanting. It may be that the precise condi- 
tions favourable for peptonization were not afforded in the 
experiments: that is a point for future investigation. But 
taking the facts as they stand, it is an inevitable conclusion 
that if in some cases, such as the Melon and the Mushroom, 
the enzyme may be regarded as a vegetable trypsin, this view 
cannot be extended to the others. It seemed to me, at first, 
that I had come upon an altogether new type of enzyme, an 
idea that occasioned a certain amount of temporary misgiving 
as to the accuracy of my observations. But it was pointed 
out to me by my colleague Professor Gotch, that within the 
last year Cohnheim (9) has described an enzyme, formed in 
the mucous membrane of the small intestine, which actively 
proteolyses peptone and casein but does not act upon the 
higher proteids. It is to this enzyme, termed ‘erepsin’ by 
Cohnheim, that the apparently new proteolytic enzyme of 
plants would correspond. It would appear, therefore, that 
plants form two distinct kinds of proteases, the one a trypsin, 
the other an erepsin ; and so far as the facts go, they indicate 
that the former is generally associated with depositories of 
proteid nutriment, such as seeds, fruits, bulbs, laticiferous 
tissue, &c., the latter with ordinary foliage-leaves, stems, and 
roots. But further research is required in order to definitely 
establish this distinction. 
I cannot too strongly emphasize the point that the results 
detailed in this paper must be taken as applying only to the 
particular season of the year during which the experiments 
were made ; that is from August to November. I have 
noticed that even within this period certain variations pre- 
sented themselves. The investigation of the various parts of 
plants, especially of leaves, at different times of the year, will 
