122 
Proceedings of the Royal Society of Edinburgh. [Sess. 
From this it will be seen that a distinct peptolytic action is found in all 
cases on Pep ton Witte, and a slight action in some cases on the protein. 
The result of the Pepton Roche experiment remained negative after several 
weeks. Neither was it determined in this case, however, if the cell 
contents obtainable by the Buchner process would be capable of hydrolys- 
ing Pepton Roche, as the small quantities of the material available did 
not allow of the use of this method. It would, however, seem probable 
that a considerable proportion of the cell contents must have been liberated 
during the grinding, since sand was employed, and since the tissue of these 
fungi is by no means difficult to disintegrate. It would therefore seem 
almost safe to assume the entire absence of this enzyme in all the cases 
in question. 
For further information, a series of experiments was carried out with 
the ordinary cultivated mushroom, which can be bought in quantities. The 
preparations were made as in the case of barley, Extract A being obtained 
by grinding in an ordinary mortar and expressing in a hand-press, while 
Extract B was obtained from the residue by the Buchner method. The 
following results were obtained : — 
Agaricus campestris. — Extract A. 
Substrate. 
Titrations. 
Average. 
Control. 
Difference. 
Protein .... 
Pepton Witte 
Pepton Roche 
5-3, 5-4, 5*3 
1-7, 1'9, 1*5 
Positive 
5*36 
P7 
result obtaine( 
6-8 
6*0 
1 within 24 ho 
1*44 
4-8 
urs. 
Extract B. 
Protein .... 
Pepton Witte 
Pepton Roche 
8-8, 9-2, 9T5 
6-8, 6*4, — 
Positive resull 
9-05 
6*6 
b obtained onh 
9-2 
73 
l after 7 days 5 
T5 
•7 
digestion. 
These results show at once the presence of a tyrosin-separating enzyme, 
and also that this, as well as the other forms present in this material, had 
been extracted in the first pressing, the amount remaining in the residue 
being doubtless removable by washing. To obtain confirmation of the 
presence of this enzyme in Agaricus, another quantity was ground with 
sand and kieselguhr and expressed in the Buchner press. Digestions similar 
to those just described were carried out with the following results : — 
