Proteolytic Enzymes in Plants 1 . 
BY 
S. H. VINES, M.A., D.Sc., F.R.S., P.L.S., 
Sherardian Professor of Botany in the University of Oxford. 
INCE the publication of my paper on tryptophane ( 1 ) in 
O the March number of the Annals for 1902, I have 
accumulated a number of new facts relating to the distribu- 
tion of proteolytic enzymes, and of tryptophane, in plants, 
which I now place on record. 
There is at present evidence that enzymes which digest 
proteids (proteases) occur in a number of isolated cases ; in 
certain lowly Algae, in some Fungi, in various Phanerogams. 
The evidence is not, however, of the 'same kind in all cases : 
in some it is direct, in others only indirect. 
The indirect evidence amounts merely to this, that the 
plants in question can be nourished by peptone or other 
proteid, no demonstration of the digestive process having 
been given. This applies to the Algae, Scenedesmus acutus , 
Chlorella vidgaris , Chlorospora limicola , investigated by Bey- 
erinck ( 2 ) ; to certain Moulds [Aspergillus niger , Penicillium 
glaucum ) ; and to the insectivorous Drosera , Dionaea , and 
Pinguicula. 
The direct evidence consists of the demonstration of the 
digestive process by means of chemical tests. This is forth- 
coming in the case of certain Bacteria, of Yeast ( Saccharomyces 
Cerevisiae ) ; and, among Phanerogams, of the insectivorous 
Nepenthes , of many seeds, of some fruits such as the Pine- 
1 A preliminary account of these observations was given at a meeting of the 
Linnean Society of London, on Nov. 20, 1902. 
[Annals of Botany, Vol. XVII. No. LXV. January, 1903.] 
