Vines. — • Proteolytic Enzymes in Plants . 249 
Leaves. 
The material used consisted usually of the tissue of the 
blade bruised in a mortar ; the petioles and mid-ribs were 
excluded as far as possible. 
Spinacia oleracea. 
In each of four bottles were placed 10 grms. of bruised Spinach 
leaves, and they were then filled with distilled water: to No. 1, 
nothing was added ; to No. 2, 1 cc. of HCN, 4 % ; to No. 3, 0-4 grm. 
of Witte-peptone ; to No. 4, 0-4 grm. of Witte-peptone and 1 cc. 
of HCN. After 18 hours’ digestion, No. 1 gave a distinct and 
No. 2 a faint tryptophane-reaction ; No. 3 gave a strong reaction, 
but as it had an offensive smell, the reaction may be attributed to 
putrefaction; No. 4 gave a marked reaction. 
Similar results were obtained with the leaves of the Dahlia, of 
Mirabilis, of Tropaeolum majus, of the Cherry-Laurel ( Prunus Lauro- 
cerasus), of Ricinus communis , of Helianthus tuberosus , and of Pelar- 
gonium zonale. 
Bras sic a oleracea. 
The results obtained with the leaves of the Cabbage were suffi- 
ciently striking to justify special mention. 
About 40 cc. of a watery extract of the leaves were placed in each 
of four bottles: to No. 1, nothing was added; to No. 2 , 1 cc. of 
4 % HCN ; to No. 3, 0-4 grm. of Witte-peptone ; to No. 4, 0-4 grm. 
of Witte-peptone, and 1 cc. of HCN. 
After 4 hours’ digestion, No. 1 gave a distinct tryptophane- 
reaction ; in No. 2 the reaction was rather stronger ; in No. 3 it was 
marked, and strong in No. 4. 
Holcus mollis. 
In this case some stem was mixed with the leaves. 5 grms. of the 
bruised material were placed with 0-3 grm. of Witte-peptone in each 
of three bottles : to No. 1 distilled water only was added (40 cc.) ; 
the material and the water were boiled before being placed in No. 2 ; 
to the water in No. 3, HCN was added to 0-18 %. After 18 
hours in the incubator, No. 1 gave a strong tryptophane-reaction, 
but smelt rather offensively ; No. 2 gave no reaction ; No. 3 a marked 
reaction. 
