1899-1900.] Dr J. S. M‘Kendrick on Enzymes in Tissues. 83 
quantity of trypsin, as the extract of the pancreas dissolved fibrin 
with the formation of peptones and crystals of leucin and 
tyrosin. Glycerine, however, extracts trypsin in small amount, 
and the solution obtained when placed with fibrin produces 
only a small quantity of peptones, and rarely crystals of leucin 
and tyrosin. To obtain a strong solution of trypsin one would 
have to adopt another method for its extraction, or to use a very 
watery solution of glycerine. 
I do not think that it is at all likely that trypsin exists in many 
of the tissues, and the probability is that the proteolytic enzyme 
of the tissues is one which is similar in nature to pepsin. 
(e) What is their Action in the Inversion of Cane 
Sugar into Dextrose 1 ? 
The only tissues where there appeared to be inversion were : — - 
1 
Rabbit. Child. 
Adult. 
Post-mortem. 
Pathological. 
Liver X 
Pancreas 
Liver X 
Fat X 
Fat X 
Bone X 
Connective 
Tissue X 
Tendon X 
Liver No. I. X 
Liver No. II. X 
Lung X 
Fat X 
L. Intestine X 
Muscle X 
S. Intestine X 
Sarcoma of face 
Tubercular sputum 
In most cases, then, the extract itself reduced Fehling and in 
almost all cases the reduction of Fehling depended on the extract, 
and not on an inversive ferment. 
The extract of the pancreas of the rabbit, however, undoubtedly 
caused inversion of the cane sugar. This is strange, as the pancreas 
is not supposed to contain an invertive ferment. In no case did I 
obtain reactions proving the presence of inversin in the intestines. 
The tubercular sputum rapidly inverted cane sugar, an action 
due probably to an organised ferment. The result is similar to that 
obtained from yeast. When the yeast is killed an organised fer- 
ment is liberated, which may be extracted by glycerine, and which 
inverts cane sugar into dextrose, as in the present instance. 
