THE VOLATILE PART OF PLANTS. 107 



observed to contain more nitrogen, by 1.2 to 1.6 per cent 

 than exists in animal casein. Furthermore, they difEer 

 from each other so widely in carbon content. (2. 7 per cent) 

 as to make it highly probable that their true composition 

 was not in all cases correctly determined. 



This conclusion is justified by the results of Chittenden 

 & Smith, who have recently analyzed five different prep- 

 arations of gluten-casein, made from wheat by Eitthau- 

 sen's method. The average of their accordant analyses 

 is given above.* Since nitrogen was determined by two 

 methods (those of Dumas and Kjeldahl) these analyses 

 wonld appear to establish the composition of gluten- 

 casein, which accordingly closely agrees with that found 

 by Ritthausen for " albumin " from barley, and with 

 that of paraglobulin, and has the same nitrogen content 

 as the casein of milk. 



The Animal Globulins agree in composition with each 

 other as well as with animal fibrin which is formed from 

 globulin (fibrinogen). The Vegetable Globulins are strik- 

 ingly different in composition, containing 1.5 to 3 per 

 cent more nitrogen and mostly but half as much sul- 

 phur. The hazel-uut conglutin and the hemp-seed vitel- 

 lin have the same composition. 



It is evident tliat the vegetable albuminoids, on the 

 whole, are distinct from those of the animal, but their 

 true composition and relations to each other, to a great 

 extent, remain to be established. 



Some Mutual Relations of the Albuminoids. — It was 

 formerly supposed that these bodies are identical in com- 

 position, the differences among the analytical results 

 being due to foreign matters, and that they difEer from 

 each other in the same way that cellulose and starch 

 difEer, viz.: on account of different arrangement of the 

 atoms. Aftei'wards, Mulder advanced the notion that 

 the albuminoids are compounds of various proportions 



* Kindly communicated by the authors. 



