156 CHEMICAL STATICS 



differs very markedly in its antigenic behavior from either of 

 its constituents. In the first place it is non-toxic, and the failure 

 to exhibit toxicity can hardly be attributable to dilution of the 

 globin constituent by admixture with casein since, as we have 

 seen, globin caseinate contains 65.5 per cent of globin (103). 

 Still more striking is the fact that it yields antibodies which 

 react (i.e., display alexin-fixation) not only with the casein con- 

 stituent of the compound, but also with the globin constituent. 

 It would appear evident, therefore, that injection of globin 

 caseinate into animals gives rise to an antibody which does not 

 appear in response to separate injections of its constituents. 

 Schmidt (111) has investigated the antigenic behavior of a com- 

 pound of globin (toxic and non-antigenic) with deutero-albumose 

 (non-toxic and non-antigenic) . The compound retains the toxicity 

 of globin and is non-antigenic. 



7. Compounds of the Proteins with Toxins, Antibodies, 

 Ferments, etc. — Very extensive evidence has been advanced by 

 numerous authors * in support of the view that the antitoxins 

 are true proteins. If this be true, and the probabilities are 

 immensely in favor of its truth, then the entire series of toxin- 

 antitoxin reactions are reactions in which proteins play a leading 

 part. To consider these here would be manifestly out of place; 

 for an analysis of the physico-chemical laws which govern these 

 reactions the reader is referred to Arrhenius (8). 



The question of the occurrence of combinations between the 

 proteolytic ferments and proteins and their significance in the 

 mechanism of protein hydrolysis will fall under consideration 

 in a later chapter (Chap. XVI) but the reader's attention is here 

 drawn to the work of Hedin (37) (38) upon this subject. 



8. Methyl and Benzoyl Derivatives of the Proteins. — Ac- 

 cording to Rogozinski (104), methylation of clupein causes pro- 

 found alteration in the composition of the molecule, reducing 

 especially the proportion of arginin yielded on subsequent hy- 

 drolysis. Skraup and Krause (114) have shown that not only 

 is arginin reduced but also tyrosin, lysin and histidin, while the 

 glutamic acid and leucin yields are unaffected. 



Blum and Umbach (19) have prepared benzoyl derivatives of 

 native and iodized proteins. 



' Cf. for literature Carl Oppenheimer (86). 



