Vines.— Proteolytic Enzymes in Plants. 261 
the tryptophane-reaction in my experiments is actually the 
chemical substance known as tryptophane. 
The formation of tryptophane in the experiments leads to 
the further conclusion that proteolysis must have taken place, 
for the presence of this substance is evidence of proteolysis. 
Hopkins and Cole (8) have* shown that tryptophane is either 
an indol-amido-propionic acid, or a skatol-amido-acetic acid : 
in either case it cannot be regarded as other than a product 
of the disruption of the proteid molecule. 
The experiments therefore prove that the various vegetable 
substances employed effected proteolysis. Inasmuch as it 
took place in the presence of antiseptics, such as HCN and 
chloroform-water, the chemical action cannot be attributed 
to micro-organisms. On the contrary, it is to be ascribed to 
a proteolytic enzyme contained in the juices or the tissues 
themselves. 
If this be so, then I have succeeded in demonstrating that 
a proteolytic enzyme is widely distributed in plants ; and it 
may be inferred that it is much more generally present than 
I have shown it to be. If it is present in plants belonging to 
the Chenopodiaceae, the Nyctaginaceae, the Euphorbiaceae, 
the Cruciferae, the Geraniaceae, the Ampelidaceae, the 
Rosaceae, the Leguminosae, the Umbelliferae, the Cucur- 
bitaceae, the Compositae, the Liliaceae, the Graminaceae, and 
the Musaceae, there is no reason why it should not equally be 
found in plants of other Natural Orders. Nor is it by any 
means confined to Phanerogams. I have demonstrated its 
presence in the Mushroom, among the Fungi ; and in the 
Hart’s Tongue Fern, among Pteridophyta. I confidently 
anticipate that it will be duly discovered in the remaining 
groups of Cryptogams, the Bryophyta and the Algae. 
The next point to be considered is the probable nature of 
the enzyme. In the previously known cases, the Pine-Apple, 
the Papaw, the Fig, Nepenthes , Yeast, Bacteria, and seeds, the 
evidence goes to prove, as I have explained in the paper (1) 
already mentioned, that the enzymes are allied to the trypsin 
of animals, since they both peptonize and proteolyse actively. 
