698 
ON MEDICINAL PEPSIN. 
In other words, A is ten times stronger than B, and twenty- 
five times stronger than C. 
3rd. That, inasmuch as coagulated albumen mixed with 
acidulated water and equal weights of D, E, and F gave not 
the slightest indication of being digested, even at the expira- 
tion of twenty-four hours from the commencement of the 
experiment, it is evident that such so-called pepsins are, to 
say the least, practically destitute of the power of digestion. 
A J, B 1, C 1, and C 2 w T ere tested in precisely the same 
manner as the other samples ; and it was found that their 
digestive powers did not materially differ from the correspond- 
ing samples A, B, and C, which, it will be remembered, were 
prepared by the same makers, but obtained from different 
sources. 
The evidence afforded by the results of the experiments 
already referred to will, doubtless, be considered quite suffi- 
cient to prove the existence of a wide difference in the 
digestive energy of certain of the pepsins met with in 
pharmacy, and the utter worthlessness of others. Never- 
theless, the following series of experiments upon fibrin was 
undertaken for the purpose of ascertaining whether or not 
the results would accord with those obtained in the previous 
investigations upon albumen. 
EXPERIMENTS UPON FIBRIN. 
In these experiments 5 grammes of finely-minced fibrin 
(lean of rump-steak) were mixed with 50 cubic centimetres 
of distilled water containing 1 per cent, by volume of concen- 
trated hj T drochloric acid, and the quantities of pepsin stated 
in the following table. Temp. 38° centigrade (lOCM 0 Fahr.); 
duration of experiment, four hours. Two comparative ex- 
periments invaaribly set going at the same time. When in 
consequence of the presence of starch, the progress of diges- 
tion could not be satisfactorily watched, the mixture was 
strained through fine muslin for the purpose previously named 
when describing the mode of experimenting with albumen. 
