42 THE ALBUMINS. 



clature established by the Kiihne school, we may designate as the 

 hemi- and the anti- complex respectively, while the third is less 

 constant and differs from the hemi- and anti- group in the presence 

 of a carbohydrate radicle and a larger percentage of oxygen, while 

 the amount of nitrogen and carbon is less than in the two other 

 groups. These three fundamental radicles are represented by the 

 three albumoses, which result primarily on proteolytic digestion, 

 viz., proto-albumose, hetero-albumose, and gluco-albumose. Of 

 these, proto-albumose represents the hemi- group, hetero-albumose 

 the anti- group, and gluco-albumose the third complex, which 

 contains the carbohydrate radicle. The essential points of difference 

 between the hemi- and anti- complex are the following : 



Hemi- group. Anti- group. 



Diamino-acids in small amount. Diamino-acids in large amount. 



Mono-amino acids in large amount. 

 Little or no leucin. Much leucin. 



No glycocoll. Entire amount of glycocoll of original 



albumin. 



Much ty rosin. No tyrosin. 



Much skatolamino-acetic acid (trypto- No skatolamino-acetic acid. 



phan). 



No carbohydrate group. No carbohydrate group. 



Contains same amount of sulphur as Sulphur the same as in hemi- group. 



original albuminous molecule, but 



only in loosely combined form. 



The anti- group owes its name to the great resistance which it 

 offers to further decomposition, by oxidizing agents, mineral acids, 

 alkalies, and proteolytic ferments, notably trypsin, all of which 

 readily decompose the hemi- group into its components. 



The extent to which the hemi-, the anti-, and the gluco- group 

 are represented in the different albumins differs to a considerable 

 extent. Casein is generally regarded as a pure hemi- body ; it con- 

 tains no glycocoll, but more tyrosin than all true albumins. Colla- 

 gen contains much glycocoll, but no tyrosin, indol, or tryptophan 

 radicles, etc. 



Of the various radicles which do not belong to the amino-acids, 

 either of the aliphatic or the aromatic series, two complexes deserve 

 especial consideration, namely, those which represent the sulphur 

 group and the carbohydrate group of the albuminous molecule. 



The Sulphur Group. Sulphur is present in all true albumins and 

 in most albumoses. According to older views, it exists in two 

 forms, one of which can be readily split off as hydrogen sulphide 

 by means of caustic alkali of moderate strength, while the other can 

 only be demonstrated after the complete destruction of the albumin- 

 ous molecule and then appears in the form of sulphuric acid. It has 

 therefore been customary to speak of a loosely combined and a firmly 

 combined group. It has further been regarded as an established 

 fact that the loosely combined sulphur is present in the intact 

 molecule in the form of a cystin complex, while nothing was known 



