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1905] DEAN—PROTEOLYTIC ENZYMES 329 
which gave a faint tryptophan reaction. The extract was examined 
in the following way: 
Flask no. 1—s5o0°¢ extract. 
Flask no. 2—so°¢ extract—boiled. 
Flask no. 3—50°¢ extract +1°° 4 per cent. HCN 
Flask no. 4—50°¢ extract +1°° 4 per cent. HCN—boiled. 
Flask no. 5—5o°¢ extract +1°° 4 per cent. HCN + 0.5 &™ Witte peptone. 
Flask no. 6—so0°° extract + 1°° 4 percent. HCN +0.5 &™ Witte peptone—boiled. 
Flask no. 7—50°° extract +0.25 Na, CO;. 
Flask no. 8—so°¢ extract +0.25 Na, CO;—boiled. 
Ten drops of toluol were added to nos. 1, 2, 7, and 8. The flasks 
were corked and placed in the incubator. After twenty hours’ diges- 
tion 10° was removed from each flask, boiled, filtered, and 1° 
of acetic acid added to each filtrate. The tryptophan test with 
chlorine water showed that proteolysis had taken place in all the 
unboiled digestions except no. 3; that in no. 1 was feeble compared 
with the action in nos. 5 and 7. These results show that although 
the enzymes of the cabbage leaves act on the proteids of the tissue, 
yet that action is slight compared with that exerted upon Witte 
peptone. The tissue residue from which the extract had been 
obtained was shaken up with water and toluol, a small portion 
temoved and boiled, and Witte peptone added to both parts. After 
two days’ digestion a sample of the fluid in each flask was tested for 
tryptophan; the unboiled digestion gave a strong reaction, the 
boiled one a very faint reaction. The fluid was removed as far as 
Possible from the unboiled digestion mixture, concentrated to a 
Sytup, treated with several volumes of alcohol to remove the pro- 
teoses and peptones, and the filtrate concentrated to a thick syrup. 
After standing, very characteristic crystals of both leucin and tyrosin 
Separated. 
Daucus Carota.—Blossoms of the wild carrot were ground 
in a mortar with water. The mashed tissue and water were divided 
into four parts and placed in test tubes. 
Tube no. 1—tissue + H,O + toluol + uncoagulated egg albumen. 
Tube no. 2—tissue + H,O + toluol + uncoagulated egg albumen—boiled. 
Tube no. 3—tissue + H,O + Witte peptone + toluol. 
Tube no. 4—tissue +H,O + Witte peptone + toluol—boiled. 
The egg albumen was added because a test of the tissues with 
