306 
ON PEPSINE. 
How is the hygrometricity to be remedied ? The inert powder 
already mentioned solves this problem, since, as soon as it is intimately 
incorporated with the extract, this ceases to attract humidity, and 
preserves a granular pulverulent form. Starch is the substance which 
best preserves pepsine from decomposition without injury to its thera- 
peutic action ; most other vegetable powders, either from the tannin 
they contain or from some catalytic force arising from their porosity, 
destroy rather than preserve it. 
The admixture of starch gives to pepsine the most convenient form. 
Corvisart has noted all the conditions that it ought to present in practice, 
viz. : — 
First. The action of the gastric juice is the dissemination of its active 
principle amongst the food, so the pepsine in powder imitates the natural 
action by the dissemination of its granules ; on the contrary, the pills, 
&c, of pepsine have an opposite effect and frequently pass into the 
intestines without action. 
Secondly. The gastric secretion does not pass into the stomach by 
the mouth before action ; so, the pepsine powder taken in wafer paper, 
commences to act in the stomach, and thus fulfils the physiological 
design ; whilst the dragees or pepsine lozenges, which, dissolve in the 
mouth, are little in accordance with it. 
Thirdly. The gastric juice is secreted drop by drop, slowly and 
successively ; so each granule of starchy pepsine evolves, in dissolving, 
its active principle, thus imitating the formation of the natural fluid. 
This is not the case with the solutions of pepsine. When administered, 
in cases where the stomach is irritable, under the form of wines and 
syrups, it is sometimes borne with difficulty. 
These conditions, which demand a preparation pure, unalterable, 
possessing always an invariable digestive power, are fulfilled by the 
" Pepsine Amylacee," or medicinal pepsine, which imitates the forma- 
tion of the gastric juice, its gradual secretion, and its slow and continual 
dissemination amongst the food. 
Mode of Extraction. — A certain number of calves' or sheep's rennets 
are taken from the animals as soon as killed, thorougly washed with 
water ; the mucuous membrane, which contains the peptic glands, is 
scraped, macerated in water, at 10° to 15° C. for twelve hours ; the 
pepsine in the solution is then precipitated by acetate of lead, allowed tp 
settle, and the supernatant liquid poured off ; a current of sulphuretted 
hydrogen is passed through the semi-liquid deposit, which precipitates 
the lead in the form of sulphide ; the pure pepsine remains in solution 
with the free acetic acid ; it is then filtered, and finally evaporated to 
dryness at a uniform temperature of 40° C. 
The next operation is the trial and determination of the dose of the 
pepsine. To determine the quantity of digestive power contained in a 
given weight, three samples are taken from the mass, the first of 25 
centigrammes, the second 50 centigrammes, and the third 75 centi- 
