Cuar. VL] DIGESTION. is 
mometer which indicated a temperature of 38° to 40° Cent. Into 
each, a quantity of unboiled fibrin was introduced, and the whole 
allowed to stand for four hours, the temperature being maintained 
during the whole time, and care being taken that each contained 
throughout an excess of fibrin. At the end of the period each liquid 
was filtered. Of the filtrate, which of course contained as much of the 
fibrin as had been digested during the four hours, 10 cub. cent. were 
measured out and evaporated, and dried at 110° as before. The residues 
were respectively— 
“ In the liquid containing hydrochloric acid 0°4079 
propionic acid 0°0601 
293 
» 4 butyric acid 0°1468 
> h valerianic acid 0:1254 
“ Hence, deducting from each of these the above-mentioned residue, 
left when the digestive liquid itself was evaporated, viz. 0°0031, we 
have, 
“For propionic acid .. es 0:0570 
sy Putyric add .. :: b ae 0:1437 
„ Valerianic acid .. i ae ue 0°1223 
as compared with 0°4048 for hydrochloric acid; these several numbers 
expressing the quantities of fibrin by weight digested in presence of 
equivalent quantities of the respective acids under identical conditions. 
“ The results of the experiment may be stated thus :—If 100 repre- 
sent 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. Ina 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 115° C., the results were as 
follows :— 
“ Quantity of fibrin dissolved in four hours by 10 cub. cent. of the 
liquid— 
“Propionic acid .. 5 — 0:0563 
Butyric acid = Ss 2 0:0835 
Valerianic acid .. z 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 .. s> ef 16°5 
Butyric acid. Ki F 24°7 
Valerianic acid .. z$ A 16'1 
“6, A third experiment of the same kind gave: 
