4 16 CHEMISTR Y OF THE DIGESTIVE PROCESSES. 
the properties of a globulin, but in the case of serum albumin no such 
formation of a globulin takes place. 1 If the proteid employed has 
previously been coagulated, no formation of a coagulable proteid is 
observed, the first product being apparently denteroalbumose. 2 
The appearances presented by proteid undergoing solution by the 
action of pepsin and of trypsin respectively, are characteristically 
different. In the case of pepsin and hydrochloric acid, the proteid 
swells up, becomes transparent or translucent, and gradually dissolves ; 
while, by the action of trypsin in alkaline solutions, the proteid does not 
swell up or become clearer, but is attacked and eroded from the outside. 
After being dissolved, the proteid is further attacked by the trypsin 
and decomposed into various products, the final result beiug a certain 
amount of peptone which is not further acted on, accompanied by 
various nitrogenous bodies, of which those occurring in largest quantity 
are two amido-acids, leucine and tyrosine. 
The primary albumoses of peptic digestion are not found among the 
intermediate products of tryptic digestion. No matter at what stage 
digestion is interrupted, no trace of either proto- or heteroalbumose is 
found ; the only albumose present is deuteroalbumose. 3 
Neumeister suggests that this may be due to the protoalbumose being 
broken up as rapidly as it is formed into amido-acids, while the heteroalbumose 
is immediately converted into deuteroalbumose. Be this as it may, the 
experimental fact is, that neither protoalbumose nor heteroalbumose are 
found at any stage of tryptic digestion. 
According to Neumeister, the deuteroalbumose present is an anti-compound 
not yielding any amido-acids Avhen subjected to the further action of trypsin. 4 
Peptone is formed much more rapidly in tryptic than in peptic 
digestion, the preliminary stages being apparently rushed through; while 
in peptic digestion scarcely any peptone is formed before complete 
conversion into albumoses has taken place, and complete peptonisation 
never occurs. 
The most essential difference between the digestive action of trypsin 
and that of pepsin lies in the discovery of Kiihne, that the action of 
the former enzyme does not cease with the formation of peptone, but 
that approximately one-half of the proteid, or of the peptone formed 
from it, is converted into a number of cystalline substances of much 
simpler composition. 
Not only does this take place in the direct tryptic digestion of proteids, 
but if peptone formed by peptic digestion be submitted to tryptic 
digestion, about one-half of it is decomposed in the above fashion. This 
experiment led Kiihne to the cleavage theory, and to naming, on the 
basis of this theory, the peptone of peptic digestion, ampAopeptone ; the 
peptone remaining after the completion of tryptic digestion, and which 
is no longer affected by renewed digestion, aw&peptone ; and that 
hypothetical substance which is supposed to form one moiety of the 
amphopeptone, and be broken up by the action of the trypsin, 
1 Neumeister, Ztschr. f. Biol., Munchen, 18S7, Bd. xxiii. S. 398 ; ibid., 1890, Bd. xxvii. 
S. 311 ; Herrmann, Ztschr. f. physiol. Chan., Strassburg, 1887, Bd. xi. S. 521. 
- When trypsin acta in an alkaline medium, alkali albumin is first formed ; but this is a 
very transient stage, the alkali albumin being quickly changed into deuteroalbumose. 
3 Otto, Ztschr. f. physiol. Ghem., Strassburg, 1883, Bd. viii. S. 129; Neumeister, 
Ztschr. f. Biol., Munchen, 1887, Bd. xxiii. S. 398. 
4 Ztschr. f. Biol., Munchen, 1S87, Bd. xxiii. S. 3S1. 
