102 HOW CROPS GEOW. 



from, which it is very difficult to separate them fully. 

 Again, if we succeed in removing foreign substances, it 

 must usually be done by the aid of acids, alkalies, and 

 other strong reagents, which easily alter or destroy their 

 proper characters and composition. Finally, if we analyze 

 the pure substances, our methods of analysis are perhaps 

 scarcely delicate enough to indicate their differences with 

 entire accuracy. 



The results of chemical investigation demonstrate that 

 the albuminoids are either identical in composition or 

 differ but slightly from each other, as is seen from the 

 Table below. The deduction of a correct atomic formula 

 from these analyses is perhaps impossible in the present 

 state of our knowledge. 



In the subjoined Table are given analyses of the albuminoids 

 which have been de-scribed. Those indicated by asterisks are recent re- 

 sults of Dr. Ritthausen ; the others are average statements of the best 

 analyses, (after Gorup-Besanez, Org. Chemie, p. 611.) 



COMPOSITION OF ALBUMINOIDS. 



Carbon. Hydrogen. Nitrogen. Oxygen. Sulphur. 



Animal albumin 53.5 7.0 15.5 22.4 1.6 



Vegetable albumin.... 53.4 7.1 15.6 23.0 0.9 



Blood fibrin 52.6 7.0 17.4 21.8 1.2 



Flesh fibrin 54.1 7.3 16.0 21.5 1.1 



Wheat fibrin* 54.3 7.2 16.9 20.6 1.0 



Animal casein 53.6 7.1 15.7 22.6 1.0 



Vegetable casein 50.5 6.8 18.0 24.2 0.5 



Gluten-casein*] 51.0 6.7 16.1 25.4 0.8 



Gliadin* ^ wheat 53.6 7.0 18.1 21.5 0.8 



Mucedin* j 54.1 6.9 16.6 21.5 0.9 



Phosphorus is not included in the above table, for the reason that in 

 all cases its quantity, and in most instances its very presence, is still un- 

 certain. Voelcker and Norton found in vegetable casein 1.4 to 2.3 per- 

 cent of phosphorus, and smaller quantities have been mentioned by 

 other of the older analysts as occurring in albumin and fibrin. The 

 phosphorus of these and of animal casein is thought not to belong to 

 the albuminoid, but to be due to an admixture of phosphate of lime. 



In his recent investigation of gluten-casein, Ritthausen found phos- 

 phoric acid that appears to have been partially uncombined with a fixed 

 base, and to have therefore resulted from phosphorus in organic conibi- 



