CLEA VAGE THEOR Y OF PROTEID DIGESTION. 419 



been such a separation, even partially, achieved, although these are admitted 

 to be ampho-bodies by the supporters of the theory. 



But if the cleavage theory be not accepted, what explanation is there 

 for the fact that different albumoses yield varying accounts of amido- 

 acids, which suffer varying amounts of decomposition, under the action 

 of trypsin ? 



The different proteids, and the products derived from them, differ so 

 little in chemical composition (and this is especially true for the various 

 albumoses), that the difference in their nature is probably due to a differ- 

 ence in atomic grouping. Is it not probable, then, that some of these 

 groups are much more susceptible of decomposition than others ; that 

 those albumoses which yield much amido-acid contain more groups in 

 their molecules which are decomposable by trypsin ; that those which 

 yield much antipeptone contain less of these decomposable groups ; and 

 that in all cases that substance (or substances) which we call antipeptone 

 is the remainder after all those groups which are attackable by trypsin 

 have been removed in the form of amido-acids ? 



It will be seen that this substitutes, for two molecules, one easily 

 attackable, the other wholly unattackable by trypsin, one molecule ; of 

 which a portion, variable in the case of each albumose, is attacked by the 

 trypsin and a residue left, in which there are no groups that the trypsin 

 is able to attack ; such a substitution relieves one from belief in a large 

 number of substances of which the existence has never been proven. 



Again, if a cleavage of the proteid molecule takes place, at the begin- 

 ning of the digestive process, into anti- and hemi-groups, of which the 

 anti-groups, after passing through the albumose stage, become finally 

 converted into antipeptone, while the hemi-groups, after passing through 

 both albumose and peptone stage, become finally converted into amido- 

 acids, one would expect, in an interrupted tryptic digestion, to find 

 these intermediate hemi-products mixed with the intermediate anti- 

 products; to find substances, corresponding to those found in peptic 

 digestion, which would become on more complete tryptic digestion 

 partially, at least, broken up into amido-acids. No such compounds or 

 mixtures are, however, actually found ; no hemi-compound is ever found 

 at any stage of tryptic digestion. As already stated, proto- and hetero- 

 albuniose are never formed, only deuteroalbumose. 



Neither is there any evidence of the formation of such a substance 

 as amphopeptone in tryptic digestion, only antipeptone is formed. In 

 short, there is no evidence whatever in tryptic digestion of two parallel 

 series of anti- and hemi-bodies proceeding pari passu into anti- and hemi- 

 peptones, of which the latter becomes decomposed into amido-acids. If 

 any hemi-bodies are formed, they are at once broken down into amido- 

 acids, without passing through the preliminary stages of hemialbumose 

 and hemipeptone ; at any rate, there is no experimental evidence of such 

 a passage. Also, when protoalbumose is obtained as a product of 

 fractional peptic digestion, and submitted to the action of trypsin, it is 

 directly broken up into amido-acids, no deuteroalbumose or hemipeptone 

 being discoverable as intermediate products. Similarly, heteroalbumose 

 is in part converted into amido-acids, and in part into aw^-deuteroalbu- 

 niose, which passes later into antipeptone without any formation of 

 /lera-i-deuteroalbumose or amphopeptone. 1 



1 Neumeister, Ztschr. f. BioL, Miinchen, 1887, Bd. xxiii. S. 381. 



