CLE A VAGE T1IE0R ) ' ( >/<' PRO TEID DIGESTION. 409 
Five hundred grms. of unboiled fibrin, squeezed as dry as possible with the 
hand, were placed al coom temperature for twenty.-four hours in 5 litres of 0-2 
per cent, hydrochloric acid ; the mixture was then heated to 37° C, and 
100 c.c. of gastric extrad added. Solution tools place inside an hour, after 
which the fluid was filtered through a hair sieve, digestion stopped by neutral- 
isation, and tli : neutralisation precipitate iiltered oft'. This precipitate is stated 
to be essentially antiarbumose. It was long washed with water, and <ti<t not 
then dissolve easily in - 2 per cent, hydrochloric acid, so was heated for some 
hours at 40 C. This aeid solution was treated with an equal volume of strong 
gastric extract in 0-1' per cent, hydrochloric acid for forty-eight hours, again a 
heavy neutralisation precipitate was obtained. This precipitate, after washing 
with water thoroughly till no biuret peptone reaction was given, was treated 
with sodium carbonate solution of 2-5 per cent., in which it was not easily soluble, 
and the solution was not clear until it had been digested for forty-eight hours at 
48" C. with trypsin. Even then, on neutralising, a precipitate behaving like 
antialbumid was obtained. Redissolved in 2*5 per cent, sodium carbonate solu- 
tion, and redigested with trypsin, it was again precipitated in clotlike flakes, 
and was only very slowly and partially converted by repeated tryptic digestion. 
Here, again, there is no guarantee, after heating the Hist neutralisation 
precipitate for some hours with 0*2 per cent, hydrochloric aeid in order 
to dissolve it, that a natural digestion product remains to be dealt with 
in the subsecpuent processes. In addition, the obstinate resistance of the 
substance to both peptic and tryptic digestion proclaims it a product of 
experimental procedure, and not a true stage in natural or uninterrupted 
digestion. 
Hemialbumose. — Kiihne and Chittenden 1 also obtained a precipitate, to 
which they gave the name of hemialbumose ; this was obtained from the pro- 
ducts of fractional peptic digestion in the filtrate after the removal of the 
so-called antialbumose by neutralisation. This filtrate was concentrated to one- 
fourth of its volume, acidilied with acetic acid, boiled and filtered from a scanty 
coagulum, again concentrated and precipitated by the addition of excess of 
alcohol. In this precipitate by alcohol, the authors recognised, besides peptones, 
two forms of albumose, soluble and insoluble hemialbumose. The precipitate 
was rubbed up with cold water, until the wash water no longer gave the biuret 
reaction. A part of the albumose (soluble hemialbumose) went into solution, 
accompanied by all the peptone, a part remained insoluble (insoluble hemi- 
albumose). The latter substance was not pure, but contained a proteid substance 
insoluble in 2 per cent, acetic acid and in sulphuric acid of - 4 per cent., and 
with difficulty soluble in dilute caustic soda solution. The " insoluble hemialbu- 
mose " was separated from this by treating with boiling water. From solution 
in boiling water a part of the "insoluble hemialbumose" was precipitated as 
the solution cooled. This was separated; the remainder was precipitated from 
the cold solution and added to it. The "soluble hemialbumose " was obtained, 
free from its admixture with peptone in the cold water extract, by Salkowski's 
method of boiling with excess of sodium chloride and dilute acetic acid so as 
to form a saturated solution, washing the precipitate with saturated sodium 
chloride solution, dissolving in water and dialysing until the dialysate gave 
no reaction for chlorides with silver nitrate. 
These hemialbumoses on tryptic digestion yielded leucine and tyrosine 
abundantly, but could not be completely broken up by such digestion, 
a variable amount of peptone being always left, no matter how" prolonged 
the digestion, which could only (on the cleavage theory) be antipeptone, 
and so pointed to impurities in the form of anti-compounds in these 
1 Loc. cit. 
