CHEMICAL BASIS OF THE ANIMAL BODY. 1183 



still more readily by the action of trypsin, so that it does not 

 make its appearance in the final products of either a prolonged 

 peptic or a short tryptic digestion. The peptone, into which 

 it may be converted by either pepsin or trypsin, is antipeptone, 

 for it cannot be made to yield any trace of leucine or tyrosine by 

 even the most prolonged and energetic treatment with trypsin, 

 and in this fact lies the distinction between antialbumose and 

 either acid-albumin or syntonin. During its peptonization by 

 trypsin some antialbumid is simultaneously formed. Antialbu- 

 mose differs from parapeptone by the fact that the latter can 

 only be peptonized by trypsin, the former by either pepsin or 

 trypsin. 



Hemialbumose. This is the best known, most characteristic, 

 and most frequently obtained by-product of proteid zymolysis. 1 

 It was first noticed and isolated by Meissner under the name 

 of a-peptone, is identical with Bence-Jones' proteid in the urine 

 of osteomalacia, and has also been known under the name of 

 'propeptone.' Of late years it has been recognized as occurring 

 not infrequently in urine, and it is more than probable that 

 many of the older statements as to the occurrence of peptones 

 in urine and other fluids referred really to the occurrence of 

 hemialbumose. It is also stated to occur normally in the mar- 

 row of bones, and in cerebrospinal fluid. Since it is readily 

 peptonized by trypsin with the simultaneous formation from 

 the peptone of much leucine and tyrosine, hemialbumose scarcely 

 makes its appearance in any appreciable quantity in the final 

 products of a pancreatic digestion. It is best prepared by 

 the action of a small amount of very active pepsin on a con- 

 siderable mass of fibrin, previously swelled up into a gelatinous 

 mass by the action of *2 p.c. HC1 at 40°. Under the action of 

 the pepsin the fibrin liquefies : as soon as this is complete, dilute 

 sodium carbonate is added until the reaction is just faintly alka- 

 line, by which means a bulky precipitate is obtained. This is 

 removed by filtration and the filtrate now contains a large 

 amount of hemialbumose and but little peptone, and may be 

 utilized directly for the tests characteristic of the albumose. 



Reactions of Hemialbumose. The pure dry substance is not 

 readily soluble in distilled water, but readily soluble in traces 

 of acids, alkalis, and neutral salts (sodium chloride). These 

 solutions give the following characteristic reactions : 



1. Acidulate fairly strongly with acetic acid and add a few 

 drops of saturated solution of sodium chloride ; a precipitate is 

 formed which disappears on warming and comes down again on 

 cooling. If excess of the salt is added the precipitate does not 

 dissolve on warming. 



1 This expression may be conveniently used to denote generally the changes 

 produced by the unorganized ferments. 



