CHEMISTRY OF PEPSIN. 
49 
liquid the proportion above indicated, complete solution 
should be effected in four hours. Agitation much promotes 
this result. 
How far the pepsin powder now supplied will bear this 
practical kind of investigation may be judged from the fol¬ 
lowing experiments, in which the preparations of two of the 
first manufacturers were employed. Fifty grains of each 
powder were weighed and respectively treated with an ounce 
of distilled water as above directed, and in the filtered 
solutions two slices of white of egg, each weighing sixty 
grains, were suspended. A temperature never exceeding 
104°, and never falling below 100° Fahr., was kept up for six 
hours, with frequent agitation of the flasks. At the'end of 
this time I found, that in one of the flasks a slight solvent 
action had been exerted, rounding the edges of the albumen, 
and rendering its substance less tough and coherent. In the 
other no alteration whatever had taken place. I then re¬ 
peated the experiment under precisely similar circumstances, 
but substituted for the solution of pepsin a like quantity of 
ordinary essence of rennet—an infusion of the stomach of the 
calf in salt and water—to which was added a few drops of 
hydrochloric acid. This rapidly disintegrated the-albumen, 
and in three hours the whole was dissolved. 
The only inference which I can deduce from these experi¬ 
ments is, that the two samples of pepsin were inert, and 
therefore absolutely without value; and as they fairly repre¬ 
sent the bulk of the preparation which is at present supplied, 
much caution should be exercised in depending upon its 
effects. The digestive power of pepsin is so easily destroyed 
by inattention to the temperature at which its solution is 
evaporated, and its assay requiring much time and care to> 
perform, I would suggest to any one anxious really to* 
investigate the therapeutic value of this remedy, the employ¬ 
ment of an extemporaneously prepared fluid by maceration 
of a washed stomach in cold water, as a substitute for- the 
powder at present in use. In the mean time the manu¬ 
facturers may see the advantage of preparing a powder 
which shall at least do that which it professes .*—Dublin 
Medical Press. 
* The beneficial effects which have been ascribed to pepsin may perhaps 
be due to the lactic acid which it contains; all weak acids are known to act 
as stimulants to the digestive organs. 
XXXIV. 
4 
