Green . — On Vegetable Ferments. 109 
is inhibitory. The products of the digestion under the most 
favourable conditions are an albumose, peptone, and both 
leucin and tyrosin. No alkali-albumin is found as is the case 
with pancreatic trypsin. Similar results were obtained with 
the vegetable proteids existing in the papau-fruit. 
This ferment was the first one known of the second group, 
which may be called the vegetable trypsins. 
The Fig, the second of these Indian fruits, has been exam- 
ined by Bouchut 1 and by Hansen 2 , who published his results 
in 1884 and 1885. He discovered in it a proteohydrolyst 
working best in an acid, but also, though less readily, in an 
alkaline medium. 
The third, the Cucumis utilissimus , Roxb., was investigated 
last year by the writer 3 , from a fruit which was grown at Kew 
from seed sent over from India by Brigade-Surgeon Bonavia. 
The ferment is found in the juice and pericarp, and is asso- 
ciated there with a globulin-like proteid. It is most effective 
in an alkaline medium, less so in a neutral one, and least of all 
in the presence of acid. Like papain, it effects a very com- 
plete decomposition of the proteid, giving rise to peptone and 
later to leucin. 
Besides these Indian plants, a proteohydrolytic enzyme 
has been ascertained to exist in the juice of the pine-apple 
(. Ananassa sativa), attention being first called to it by Marcano 
of Venezuela 4 in 1891. The fruit was subsequently investi- 
gated in some detail by Chittenden 5 , and his results have 
recently been published. The ferment exists in the unaltered 
juice of the pine-apple, which is found to have a profound and 
rapid digestive effect on such bodies as fibrin and egg-albumin, 
converting them into proteoses, and peptones with formation 
of both leucin and tyrosin. It is hence a tryptic ferment like 
papai'n. The powers of the juice are seen best in a perfectly 
neutral solution, a little acid quickly diminishing its activity. 
1 Compt. Rend. July 1880. 
2 Biol. Centr. 1884, also Arb. d. bot. Inst, in Wurzburg, iii. 1885. 
3 Ann. of Botany, vol. VI, 1892. 
4 Bulletin of Pharmacy, vol. V, p. 77, 1891. 
5 Trans, of Connecticut Academy, vol. VIII, 1891. 
