The results of the experiment may be stated thus: If 100 represent the
digestive power of a liquid containing pepsin with the usual proportion
of hydrochloric acid, 14.0, 35.4, and 30.2, will represent respectively
the digestive powers of the three acids under investigation.
5. In a second experiment in which the procedure was in every respect
the same, excepting that all the tubes were plunged into the same
water-bath, and the residues dried at 115o C., the results were as
follows:
Quantity of fibrin dissolved in four hours by 10 cub. cent. of the
liquid:
Propionic acid 0.0563 Butyric acid 0.0835 Valerianic acid 0.0615
The quantity digested by a similar liquid containing hydrochloric acid
was 0.3376. Hence, taking this as 100, the following numbers represent
the relative quantities digested by the other acids:
Propionic acid 16.5 Butyric acid 24.7 Valerianic acid 16.1
6. A third experiment of the same kind gave: [page 91]
Quantity of fibrin digested in four hours by 10 cub. cent. of the
liquid:
Hydrochloric acid 0.2915 Propionic acid 0.1490 Butyric acid 0.1044
Valerianic acid 0.0520
Comparing, as before, the three last numbers with the first taken as
100, the digestive power of propionic acid is represented by 16.8; that
of butyric acid by 35.8; and that of valerianic by 17.8.
The mean of these three sets of observations (hydrochloric acid being
taken as 100) gives for
Propionic acid 15.8 Butyric acid 32.0 Valerianic acid 21.4
7. A further experiment was made to ascertain whether the digestive
activity of butyric acid (which was selected as being apparently the
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