( 420 ) 
substance is precipitated as a gelatinous mass, at the surface of 
which a clear layer of alcohol gradually separates, which retains but 
little of the substance in solution. The precipitate, was first washed 
by decantation with 96°/) alcohol and then mixed with equal 
volumes cf alcohol and ether, when it becomes flaky and deposits 
well. It is at last brought on the filter, washed with pure ether 
and dried. When drying the precipitate which was first of a pure 
white, sometimes acquires a light yellow tint. 
This substance has the qualities of an acid. Brought into water, 
it is dissolved, with an acid reaction if an alkali be carefully added. 
When this acid reacting solution is subjected to electrolysis, under a 
tension of + 50 Volt, in the way lately described by Hurskamp !) 
after being freed as much as possible from other salts, by dialysing 
into repeatedly renewed distilled water for a few days, then the 
proteid is transported to the anode and is there deposited as a 
gelatinous lump, while at the negative pole alkali is accumulated. 
I propose to give to this substance the name of pepsinic acid. 
Out of the alcoholic solution the substance separates by evaporation 
of the alcohol, as a varnish-like substance. It gives biuret and xantho- 
protein-reaction and the reactions of ADAMKIEWICZ and of MILLon. 
As might be expected it does not yield sulfur, when boiled with 
hydrate of potassium. By boiling for a long time with alkali it is 
changed further. Addition of hydrochloric acid then no more causes 
any precipitate. 
Out of pepsin solutions, which are changed by heating slowly 
without becoming turbid by this, this substance cannot be obtained. 
I first became acquainted with the pepsinic acid as a decomposition 
product of the pepsin, prepared out of the mucous membrane of 
the pig’s stomach and I afterwards obtained it in exactly the same 
way out of the pepsin of the dog. However I never succeeded in 
preparing the pepsinic acid of the pig entirely colourless. Therefore 
I did not use this for elementary analysis. 
The analysis of the pepsinic acid of the dog gave the following results: 
C H N 5 
BO 1.02 14,44 1.08 
whereas for the coagulation-product, out of which this acid is 
prepared and which may be considered as an acid proteid matter 
itself, was found: 
C H N S 
50.35 6.98 14.90 1.64 
1) Zeitschr. f. Physiol, Chemie; Bd, XXXIV, 5. 32, 
