202 Green . — On the Occurrence of Vegetable Trypsin, etc, 
nearly free from admixture, and were finally allowed to form 
very slowly in a watch-glass. Those from G were found, 
when examined under the microscope, to be of two kinds, the 
rosettes already spoken of, and others having the character- 
istic appearance of leucin crystals aggregated into rough 
rounded clumps. Those from H, as before, only showed the 
doubly refractive rosettes. 
G then contained crystals of two kinds, H only one, and 
those absent from H were found to resemble leucin in appear- 
ance. The doubly refractive rosettes were present in the 
two extracts in about equal amounts. These were probably 
present in the fruit before extraction, while the leucin was 
formed during the digestion. 
From the crystallised residue of G so obtained, several of 
the rounded clumps were separated and carefully dried. They 
were then put into a small hard glass tube and heated strongly 
in a flame. They sublimed without melting, and were de- 
posited again in crystalline form on the upper cool portion 
of the tube. This is strong confirmation of their being leucin, 
as this is the only body derived from proteo-hydrolytic decom- 
position of albumin that will sublime unchanged. 
I had unfortunately at this point come to the end of my 
material, and was therefore unable to investigate the ferment 
further in the direction of isolation. 
To summarise my results, I find that : — 
(i) The fruit of Cucumis utilissimus , Roxb., contains in its 
juice and in its pericarp a proteo-hydrolytic ferment, capable 
of dissolving coagulated egg-albumin. 
(a) This ferment is either globulin in nature, or associated 
with a globulin in the cells of the plant. 
( 3 ) Like papain, it works best in a slightly alkaline medium ; 
less readily in a neutral one, and least of all in the presence 
of acid. 
(4) Like papain, again, it effects a very complete decom- 
position of the albumin, giving rise to peptone, and later to 
leucin. It is a ferment, therefore, allied to the trypsin, rather 
than to the pepsin, of the animal organism. 
