170 



CHEMISTRY OF PLANT LIFE 



COMPOSITION OF PLANT PROTEINS 



The distribution of the different amino-acids in some of the 

 different plant proteins which have been examined in this way is 

 shown in the following table : 



At the time when these analyses were made, a method for the 

 quantitative estimation of tryptophane had not been devised, 

 although one is now available. The addition of the percentages of 

 tryptophane and of other amino-acids for which methods of deter- 

 mination are not yet known, would bring the total, in each case, 

 more nearly up to the full 100 per cent. These data will serve to 

 show how widely the different plant proteins vary in the propor- 

 tions of the different amino-acids which they contain. Animal 

 proteins have been found to be still more variable in composition. 



In the use of the proteins as food for animals, it appears that 

 the different amino-acids are in some way connected with the 



