THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[March 30, 1872. 
784 
tion, did not act at all on albumen, ,? which remark 
I herewith revoke as erroneous. The fact was, that 
intending to make pure pepsin and not getting a 
precipitate by alcohol in the sour solution, I added 
carbonate of soda to neutralize the acid, and then 
obtained by alcohol a precipitate which I believed 
to be pure pepsin; at that time I had not studied 
the change which carbonate of soda produces in 
pepsin. 
When I say above the pepsin is destroyed, I mean 
its action on fresh coagulated albumen. A pepsin 
solution, made entirely neutral, or rather a little 
alkaline by addition of carbonate of soda, which 
afterwards is acidulated again with hydrochloric 
acid, lias lost its power to dissolve fresh coagulated 
albumen. 
The alkaline solution assumes a foul odour after 
a short time; it does not act on fresh coagulated 
albumen, except when putrefaction sets in, and then 
the more putrid the solution becomes, the more it 
seems to act on albumen; at the same time the 
most natural odour of healthy human faeces will 
show itself. 
But, on the other hand, the alkaline solution, by 
itself as well as when acidulated, dissolves partly 
digested albumen. 
Coagulated albumen, put into pepsin solution 
until half gone, then taken out on a cloth and 
washed and put into an alkaline pepsin solution, 
will dissolve ; it will likewise dissolve in an alkaline 
solution which has been again acidulated by the 
addition of hydrochloric acid. But these solutions 
have a different appearance from a solution by pep¬ 
sin ; they are not as clear and thin a liquid as the 
latter. 
An alkaline (modified) pepsin solution does not 
get precipitated by chloride of sodium, but upon ad¬ 
dition of hydrochloric acid, a copious gelatinous pre¬ 
cipitate will be immediately formed. 
Digestive Power of Pepsin. —In 1113 " former ex¬ 
periments the strength of pepsin was ascertained 
by allowing its solution at a certain temperature to 
act upon a convenient quantity of coagulated albu¬ 
men for a given time, and determining the quantity 
dissolved by weighing that undissolved; the albumen 
by this method was only partially dissolved. In my 
recent experiments I determined the strength by 
ascertaining the amount of albumen that would be 
fully dissolved hi a certain time and at a given 
temperature. I had found that the solvent power 
of pepsin is not in inverse proportion to the time; 
for if a pepsin dissolves x albumen in s time, 2 a 
pepsin will not dissolve x albumen in | tune, as 
might be supposed, but require longer time. The 
last portion of coagulated albumen to be dissolved 
in an experiment requires much longer time in pro¬ 
portion, even when pepsin is in excess. 
Having used heretofore, in my experiments with 
pepsin, 10 drops of hydrochloric acid to the fiuid 
ounce of water, I wished to determine whether or 
not a smaller quantity of acid would answer the 
same purpose. It was of importance to ascertain if 
by the preparation of liquid pepsin a smaller quan¬ 
tity of acid would produce the same results, as some 
complaints were made of the acidity of that prepara¬ 
tion as first prepared. 
Of four experiments, in which a certain quantity 
of pepsin was dissolved in 1 ounce of ivater with 
respectively 4, G, 8 and 10 drops of hydrochloric 
acid of 1T7 sp. gr., the same amount of coagulated 
albumen was dissolved in the shortest time where G 
drops, next where 8 drops, and thirdly, where 10 
drops of acid were employed ; while the experiment 
containing 4 drops of acid had, after six hours, a 
considerable quantity of albumen not dissolved. I 
therefore made all my subsequent experiments with 
a solution containing 0 drops of hydrochloric acid 
to the fluid ounce of water, at a temperature of 100 ° 
to 105° F., and each vial was shaken about every 
ten minutes. 
One grain of purified pepsin in 4 oz. of acidulated 
water was found to dissolve 400 grs. of coagulated 
albumen in eighteen hours at 7 5 ° F. 
One grain of purified pepsin in 4 oz. of acidulated 
water dissolves 500 grs. coagulated albumen at a 
temperature of 105° F., in six hours. 
Ten ( 10 ) grains of saccharated pepsin dissolve 120 
grs. of coagulated albumen in four to six hours, at 
100 ° F. 
Although I did not succeed in preparing a pepsin 
like Wasman’s, of which one part was capable of 
dissolving GO,000 parts of coagulated albumen, I 
found that the digestive power of pepsin was almost 
inexhaustible. 
With one-lialf grain of purified pepsin in 2 oz. of 
acidulated water I dissolved 250 grains of coagulated 
albumen ; to the solution was added another ounce 
of acidulated water and 250 grs. of albumen; when 
it was again dissolved I added acidulated water and 
albumen in the same proportions, until finally the 
one-lialf grain had dissolved 1500 grs. of coagu¬ 
lated albumen. That it would have dissolved still 
more I proved in an experiment, mentioned here¬ 
after. 
Pepton Solution. —When the albumen, which by 
the digestive process is converted into albuminose 
or pepton, is perfectly dissolved, the resulting pep¬ 
ton solution is a very limpid, thin, slightly yellowish- 
coloured liquid, which, when filtered, has an opales¬ 
cent appearance. 
By addition of alcohol it remains at first clear, 
but forms, after twenty-four hours, a gelatinous pre¬ 
cipitate. 
Pepton Precipitate. —An equal volume of satu¬ 
rated salt solution added to the pepton solution pro¬ 
duces a copious, perfectly white precipitate, which, 
upon being collected on a filter, drained, pressed 
and dried, yields a hard white substance containing 
pepsin, pepton, chloride of sodium and a little acid. 
Put into water it becomes translucent, like horn, 
and dissolves after some time. 
Its solution has an acid reaction, and is not coagu¬ 
lated by heat; lrydrocliloric acid produces a heavy 
precipitate which, by dilution with water or by 
addition of more acid, will redissolve; with alcohol 
it becomes opalescent and forms after some time a 
precipitate. 
Bichloride of mercury gives a heavy white pre¬ 
cipitate. 
Coagulated albumen put into the watery solution 
is hardly acted upon, but when acidulated with hy¬ 
drochloric acid it is dissolved. 
Digestive power of the Pepton Precipitate. —The 
digestive power of the precipitate, obtained by addi¬ 
tion of sodium chloride to the pepton solution is 
remarkable. I 11 many cases a solution of 1 gr. of 
the precipitate in 1 oz. of acidulated water dissolved 
100 grs. of coagulated albumen. 
With 20 grs. of saccharated pepsin in 2 oz. of 
acidulated water I dissolved 240 grs. of coagulated 
