CHEMISTRY OF PEPSIN. 
45 
digestion only after admixture with the biliary and pan¬ 
creatic secretions. For the proper solution of the food in 
the gastric juice, heat and motion are two essential conditions. 
If the temperature of the stomach be lowered, digestion is 
much impaired; but then, on the other hand, if it be 
elevated above 120° the function is altogether checked. The 
action of gastric juice upon nitrogenized matter has often 
been carefully observed, not only in cases where the secretion 
has been obtained by fistulous openings into the stomachs 
of dogs, but, as in the well-known case of St. Martin, in the 
human subject. If a piece of coagulated albumen, for 
example, be suspended in a phial containing gastric juice, 
and the phial be placed in water which is kept at a tem¬ 
perature of 100° Fahr., after a short time the surface of the 
albumen becomes decomposed, and its edges become rounded. 
By slightly shaking the phial the pulpy matter which invests 
the mass is removed and dissolves in the fluid, exposing 
a fresh surface to its action, and if this be continued for a 
few T hours the whole will be dissolved. Such a solution 
of albumen is very different in its constitution and pro¬ 
perties to the solution obtained by dissolving albumen in a 
dilute acid ; for while the gastric solution readily passes into 
the circulation, it has been demonstrated by Bernard that 
the latter is carried off with the urine. Attempts have been 
made to estimate the probable amount of the gastric fluid 
which is secreted in the twenty-four hours, from the assump¬ 
tion that a fixed quantity of the secretion is capable of 
digesting a certain weight of anhydrous fibrine or albumen. 
Not only must, in my opinion, such a mode of calculation 
be deemed fallacious, seeing that there is no evidence that 
the secretion of the dog, which has always been the subject 
of the experiments, resembles that of man with sufficient 
accuracy to admit of the deduction from one of facts which 
should apply to the other, but 1 find that the statements of 
different chemists as regards the solvent power itself differ so 
widely that we must cease to regard their results as even 
approximations to general truth. Thus, for instance, ac¬ 
cording to Lehmann, about twenty parts of the gastric juice 
of the dog are required for the digestion of one part of 
albumen. From these data the amount daily secreted by a 
healthy man must be from sixty to eighty ounces.* But if 
we are to believe Boudault, who is one of those who have 
* It lias been stated by Schroder to amount to a little more than 30 
i pints.—E d. Chem. News. 
