1 1 8 Vines . — The Proteases of Plants {IV). 
To return to the interpretation of my own results. Peptolysis and 
fibrin-digestion both took place : but the question remains, were they 
effected by a single protease of the nature of tryptase ; or were they effected 
by two distinct proteases, the one an ereptase, the other possibly a peptase ? 
Dean recognizes the presence of ereptase in the seeds of Phaseolus 
vulgaris , and the facts that I have recorded seem to extend this conclusion 
to the various seeds with which I have experimented. The important point 
is that, whereas the production of tryptophane was immediate, the digestion 
of fibrin was delayed, the less so the longer the seeds had been germinating 
before the experiment. This difference in point of time suggests that two 
distinct proteases are concerned in the proteolysis of the seed : were both 
tryptophane-production and fibrin-digestion effected by one and the same 
enzyme, the two processes should be carried on more nearly pari passu 
than was observed to be the case. However, it is not urged that the results 
are absolutely conclusive. 
With the object of obtaining some more definite answer to this important 
question, I instituted a series of experiments with ungerminated seeds of 
the same plants and from the same parcels. I must explain that in some 
cases the seeds were used with their integuments, though I did not observe 
that this made any material difference. In other respects the methods 
employed were the same as those already described. 
( 2 ) Ungerminated Seeds. 
The experiments themselves require no special description, and were 
exactly the same in all cases : so the results may be at once considered. 
The 10 °/ o watery mixtures of the six species of seed investigated 
gave no tryptophane-reaction, to begin with, except in the case of Lupin us 
hirsutus , where a faint reaction was detected. This being so, the develop- 
ment of a tryptophane-reaction, whilst in the incubator, would be evidence 
of autolysis ; and, as a matter of fact, tryptophane was produced in every 
instance, with various degrees of rapidity, but rather slowly and gradually 
as a rule, as indicated in the following table compiled from a number of 
experiments : — 
24 hrs. 
48. 
72 . 
96. 
120. 144. 
Vicia Faba .... 
— 
distinct 
marked 
— 
— strong 
Phaseolus 7 nultiflorus . 
faint 
— 
marked 
strong 
Pisum sativum . . . 
faint 
distinct 
— 
marked 
strong 
Lupinus hirsutus . 
Phaseolus vulgaris 
Zea Alais .... 
strong 
faint 
faint 
marked 
distinct 
strong 
marked 
strong 
In every experiment, then, evidence of autolysis was obtained : clearly 
a protease was present in the ungerminated seeds that could act upon 
