CLE A I A GE THEOR V OF PRO TEW DIGESTION. 4 ' 7 
// 1 //upeptone. It will be seen from this that the term hemipeptone is 
a term for something which has ;i .-<-] .<n-ate existence only in theory. 
There has as yet beeo no method either devised or fallen upon by 
accident of separating these two substances which are Bupposed by the 
cleavage theory to be present, mixed in equal proportions, in ampho- 
peptone. This is somewhat remarkable, in view of the number of years 
the theory has now been in vogue, and the large amount of experimental 
work that has been carried out in connection with it, and ought to be 
looked upon as an indication, either that amphopeptone is not really 
a mixture of antipeptone with a hypothetical hemipeptone, but a 
substance capable of breaking up under the action of trypsin into a new 
peptone (antipeptone) and a number of amido-compounds ; or that anti- 
and hemipeptones are not separately present in amphopeptone, but that 
this peptone breaks up upon the further action of trypsin into antipeptone 
and hemipeptone, and that this hypothetical hemipeptone is next acted 
upon and broken into simpler bodies, finally yielding leucine, tyrosine, 
and the other companions of antipeptone found in complete tryptic 
digestion. 
The decomposition of proteids by trypsin is represented by 
Neumeister x according to the following schema : — 
Proteid. 
I 
Deuteroalbumose 
I 
Amphopeptone 
I I 
Antipeptone Hemipeptone 
III I 
Leucine Tyrosine Aspartic Acid Tryptophan, etc. 
According to the same author, several deuteroalbumoses are formed, in the 
course of tryptic digestion, yielding corresponding amphopeptones. He also 
states that all the albumoses up to the present known, whether formed in 
peptic or tryptic digestion, are amphoalbumoses, — that is to say, yield both 
antipeptone and amido-acids on complete tryptic digestion. The ratio between 
the amounts of antipeptone and of amido-acids is a very variable one ; 
heteroalbumose, for example, yielding much antipeptone and little amido-acid, 
while protoalbumose breaks up into much amido-acid and very little anti- 
peptone. Those who hold the cleavage theory explain this by saying that 
heteroalbumose is to a large extent an anti-substance, and protoalbumose 
almost purely a hemi-substance ; but the experimental facts may be met 
equally well by the statement, that heteroalbumose is an albumose of such a 
chemical nature that it breaks up under the action of trypsin so as to yield a 
large percentage of peptone unalterable by further action of trypsin, accom- 
panied by a small amount of amido-acids ; protoalbumose is an albumose 
different in nature from heteroalbumose, and yielding, on further tryptic 
digestion, very little peptone (antipeptone) and a large amount of the amido- 
acids. There is no more proof that either heteroalbumose or protoalbumose is 
such a mixture of albumoses as the cleavage theory demands, than there is 
that amphopeptone is such a mixture of the corresponding peptones. 
All the observed facts of peptic and tryptic digestion may be simply 
represented by the following schema, without any reference to the 
1 " Lehrbuch der physiologischen Chemie," Jena, 1893, Th. 1, S. 200. 
VOL. I. — 27 
