Vines . — Proteolytic Enzymes in Plants . 247 
Euphorbia Characias. 
The latex from green herbaceous shoots is slightly acid, and gives 
no tryptophane-reaction. 
An extract was made by grinding up some shoots (without leaves) 
with distilled water. About 25 cc. of the extract were placed in each 
of three bottles : to No. 1 nothing was added ; to No. 2, a few drops 
of 4 % HCN; to No. 3, a few drops of HCN and 0*25 grm. of 
Witte-peptone. 
After 5 hours’ digestion, No. 3 gave marked tryptophane-reaction ; 
Nos. 1 and 2 gave none: 17 hours later, the reaction was strong in 
No. 3, doubtful in No. 1, absent in No. 2. 
Lactuca saliva. 
The bruised leaves of the Lettuce were used : 10 grms. of bruised 
leaf were placed in each of four bottles filled with distilled water 
(40 cc.) ; to No. 1 nothing was added ; to No. 2, 1 cc. of 4 % 
HCN ; to No. 3, 0-3 grm. of Witte-peptone ; to No. 4, 0*3 grm. of 
Witte-peptone and 1 cc. of 4 % HCN. 
After 3 hours in the incubator, no tryptophane-reaction was 
given in any case : 18 hours later, a faint reaction was given by 
Nos. 1 and 2, a strong reaction by No. 3, and a marked reaction 
by No. 4. 
Some experiments were made with the root and leaf of the Dande- 
lion : but the liquids became so deeply coloured that the tryptophane- 
reaction was uncertain. 
The measure of success that had been met with in the 
experiments with fruits and with laticiferous plants suggested 
to me the possibility of obtaining similar results with the 
stems, leaves, and roots of ordinary plants, which I accordingly 
proceeded to investigate. 
Stems. 
The material employed was either pieces of stem bruised in 
a mortar, to which about 40 cc. of distilled water were added, 
or the expressed juice of the stem in the same quantity. 
Dahlia variabilis. 
5 grms. of bruised stem were placed in each of five bottles : to No. 1, 
nothing was added but 35 cc. of distilled water ; to No. 2, was 
