Vines. — Proteolytic Enzymes in Plants. 253 
0*5 grm. of moist fibrin, and to (1) HC 1 to 0*2 %, to (2) citric 
acid to 1 %. After 24 hours’ digestion, the fibrin had disappeared 
in (1), and there was but little left in (2). The juice gave marked 
tryptophane-reaction to begin with. 
In a second experiment, a green, quite unripe Cucumber was used : 
the juice gave no tryptophane-reaction. 
50 cc. of juice were placed in each of two bottles with 1 grm. of 
moist fibrin: (1) was acidified with HC 1 to 0-2 %; (2) with citric 
acid to o*5 %. A third bottle (3) contained only juice. 
After 2 hours’ digestion, the contents of (1) and (3) gave a marked 
tryptophane-reaction ; those of (2) a distinct reaction : this is clearly 
due to the digestion of the proteids of the juice. 
After 24 hours’ digestion, the fibrin in (i) and (2) had perceptibly 
diminished; after 48 hours it had disappeared in (1), and there was 
very little left in (2). 
Euphorbia Characias. 
A watery extract was made of the soft parts of some stems, without 
leaves : the extract gave no tryptophane-reaction. 30 cc. of the 
extract were placed in each of four bottles: to (1) nothing was added, 
to the other three 0-5 grm. of moist fibrin; (3) was acidified with HC 1 
to o-2 % ; (4) with citric acid to 1 %. 
After 18 hours’ digestion, (1) and (2) gave a distinct, (3) a marked, 
and (4) a strong tryptophane-reaction; in (2), (3), and (4) the fibrin 
had diminished. After 45 hours’ digestion, there was still a little 
fibrin left in (3), and rather more in (2) and (4); all three gave a 
strong tryptophane-reaction, whilst that of (1) had remained distinct. 
Wheat- Germ. 
5 grms. of finely ground ‘germ’ were extracted with 100 cc. dis- 
tilled water: the extract gave no tryptophane-reaction. 50 cc. of 
extract were placed in a bottle (1) with 0*25 grm. moist fibrin, and 
acidified with HC 1 to o-i % ; 20 cc. of extract were placed in another 
bottle (2), nothing being added. 
After 23 hours’ digestion, the fibrin in (1) was found to have 
diminished, and the liquid gave distinct tryptophane-reaction ; the 
liquid in (2) gave a faint reaction. After 28 hours’ digestion, the 
fibrin had disappeared in (1), which now gave a marked tryptophane- 
reaction ; (2) gave a distinct reaction. 
