14 Vines . — The Proteases of Plants ( VI). 
Those in the latter paper were a more detailed re-examination of Yeast 
and of the Mushroom ; and it is worth while to repeat here the conclusion 
to which I was led: ‘It is suggested that the Yeast and the Mushroom 
contain two associated proteases, vegetable erepsin and vegetable 
trypsin . . . J 
My next paper ( 18 , Jan. 1905) contains an account of further experi- 
ments upon both new and old material, confirmatory of those already 
described. Perhaps the most important observation recorded here is the 
discovery that the leaves of Phytolacca decandra , unlike all the leaves 
(except those containing latex) previously examined, readily digested fibrin. 
Another paper which followed closely ( 39 , April 1905) upon the 
preceding, raised the question, ‘ What is the nature of the fibrin-digesting 
protease ? 5 I had observed, when testing the action of various antiseptics 
upon the digestive processes, that sometimes the fibrin-digesting property 
of an extract or a tissue was destroyed by an antiseptic, whilst the peptone- 
splitting activity remained unimpaired, and vice-versa. This paper is a 
study of the action of acids and of alkalies upon the digestive processes in 
a variety of plant-material (papain, Pine-apple juice, Yeast, Mushroom, 
Malt, Hyacinth-bulb, pitcher-liquid of Nepenthes). My conclusions were as 
follows : ‘ The experiments detailed in the foregoing pages constitute 
a demonstration of the differential effect of varied reaction upon the 
proteolytic activities of the juices and extracts of certain representative 
plants. . . . On further consideration of these results, it will, I think, be 
generally admitted that the method employed does actually afford the 
means of realizing that separation of the proteolytic activities which I 
postulated as being essential to the investigation of the nature of the 
supposed “vegetable trypsin”. I cannot interpret the evidence thus 
obtained otherwise than as indicating that peptolysis and fibrin-digestion 
are effected by two distinct proteases ; that “ vegetable trypsin ” is, in fact, 
not a single protease, but a mixture of two ; the one a peptolytic enzyme 
belonging to the ereptases, the other a peptonizing, fibrin-digesting, enzyme 
belonging to the peptases. ... If it be admitted that two proteases, or two 
groups of proteases, exist in plants, the ascertained facts as to the distribution 
of the proteases in the vegetable kingdom may be succinctly stated in the 
following propositions : All plants that have been examined contain 
ereptase ; in some of these plants the ereptase has been found to be 
associated with a larger or smaller proportion of a peptase ; in no plant 
has a peptase been found to exist unassociated with ereptase ’. 
This altogether new view of the nature of the plant-proteases was 
a challenge to the idea of ‘ vegetable trypsin 5 ; but the evidence was as yet 
insufficient to be convincing. The kind of evidence still required was the 
actual separation of the two kinds of enzymes, the peptase and the ereptase, so 
that from the same material there should be prepared extracts, one of which 
