4 io CHEMISTR Y OF THE DIGESTIVE PROCESSES. 



hemialbumoses (or otherwise to the non-existence of cleavage at the 

 albumose stage into hemi and anti groups). Nor, when these hemi- 

 albumoses were subjected to more prolonged digestion yielding hemi- 

 peptone (?), could this substance be completely broken up by prolonged 

 tryptic digestion. 



Kiihne l also described as hemialbumose a substance occasionally found in 

 the urine of patients suffering from osteomalacia, and first discovered by 

 Eence Jones. Much has been made of the importance of this albumose by 

 the supporters of the cleavage theory, but there is no more evidence that it is 

 a pure hemialbumose than there is in the case of the substances described 

 above ; that is to say, it has not been shown to be completely broken up by 

 tryptic digestion, and this is the crux of the whole question. The fact that it 

 yields leucine and tyrosine proves nothing. It has not been experimentally 

 shown that no peptone is left after the prolonged action of trypsin upon it. 



Separation of the various albumoses from the " hemialbumose " pre- 

 cipitate. Stimulated by a desire to obtain a pure hemialbumose which 

 should be capable of complete decomposition past the peptone stage by 

 trypsin, and encouraged in the belief that hemialbumose was a mixture, 

 as well by the known existence of two physically different forms (the 

 soluble and insoluble described above) as by certain inconstancies in its 

 behaviour towards sodium chloride, Kiihne and Chittenden 2 set to work 

 again upon the subject, and although they did not quite achieve their 

 object, produced a research which, whether the cleavage theory stands 

 or falls, must, from the experimental point of view, always remain of the 

 highest value, containing as it does the first basis for a classification of 

 the albumoses, the first light cast upon the relationship of this class 

 of proteids. 



From the hemialbumose described in their previous paper, they were 

 able to separate, by the action of sodium chloride under various 

 conditions, four substances with the following properties : 



1. Protoalbumose. Precipitated by saturation with sodium chloride, 

 soluble in cold and hot water. 



2. Heteroalbumose. Also precipitated by saturation with sodium 

 chloride, but insoluble in cold and in boiling water ; soluble in dilute and 

 in moderately concentrated saline solution. 



3. Dysalbumose. The same as heteroalbumose, but insoluble in 

 saline solution. This solution was recognised to be merely a more 

 insoluble modification of heteroalbumose ; each of the two substances is 

 easily convertible into the other. Dysalbumose corresponds to the 

 " insoluble albumose " of the earlier paper. 



4. Deuteroalbumose is not precipitated by saturation with sodium 

 chloride alone, but is precipitated by saturation with sodium chloride in 

 the presence of acetic acid, and is soluble in water. 



These various albumoses were subjected to tryptic digestion, and it 

 was found that none was a pure hemialbumose, all yielded more or less 

 unconvertible peptone accompanied by leucine and tyrosine. A bigger 

 yield of amido-acids was obtained from protoalbumose and deutero- 

 albumose than from heteroalbumose ; indeed, the latter showed itself to 

 be more an anti- than a hemi- body, while protoalbumose yielded very 

 little peptone and an abundance of amido-acids. After this evidence 



1 Ztschr.f. BioL, Miinclien, 1883, Bd. xix. S. 209. 



2 Ibid., 1884, Bd. xx. S. 11. 



