Cuar. VIL] DIGESTION. 75 
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— 
“Tn the liquid containing hydrochloric acid 0°4079 
Fe 5 propionic acid 0*0601 
35 3 butyric acid 0°1468 
93 ss 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 .. 26 ae be 0°0570 
-y, butyric acid... 2s vats ws 0°1437 
a valerianic acid .. ‘een se a 01223 
as compared with 0°4048 for hydrochloric acid; these several numbers: 
expressing the quantities’ of fibrin by. weight digested in presence of 
equivalent quaritities 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 sedond experinient 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 :— . ‘ F ; 
“ Quantity of fibrin “dissclved in four hours by 10 cub. cent: of the’ 
lquid— Tenors reeds : eae 
: “Propionic. acid’ |. a os 0°0568 
Butyric acid =. te # 0+0835 
Valeriani¢ acid’ ”.: is «070615 
“The quantity digested by a similar liquid containing hydrochloric 
acid was 0-3376.1'Hehee, taking this as 100, the following numbers 
represent the relative quantities digested by the other acids:. 
“Propionic acid... e165 
Butyric acid’. we es 24:7 
Valerianic acid .. ys i 161 
«6, A third experiment of the same kind gave: 
