O'Brien . — The Proteids of Wheat, 175 
wheat. But his work is noteworthy rather for his elucidation 
of the similarity of animal and vegetable proteids than as 
regards our special subject. To him we owe not only the 
name ‘ proteid,’ but also the xanthoproteic reaction. 
Liebig 11 and his school working at vegetable proteids gave 
considerable attention to the proteids of wheat, in which they 
distinguish an albumin and gluten. In the separation of 
gluten into its constituent parts Liebig does not proceed 
further than to zymom and glian (fibrin and Pflanzenleim ) ; 
he does not consider it necessary to isolate mucine, for the 
two substances described agree so closely in chemical compo- 
sition with crude gluten that the presence of a third, 
essentially different, substance is improbable. 
Both albumin and Pflanzenleim (glian) are described by 
him as practically identical with egg-albumin ; zymom only 
differs in its greater insolubility and is for the first time 
clearly identified with animal fibrin. Animal casein is not 
represented in wheat, but replaces gluten in leguminous and 
in oily seeds. 
( Albumin n , , ( Albumin 
Wheat Proteids < j Fibrin [zymom] er see s ( Casein(Legumin) 
( u e ( Pflanzenleim [glian] 
About the same time the French chemists, Dumas and 
Cahours 13 , were also working out the identity of animal and 
vegetable albuminous substances, and investigated the albumin 
and gluten of wheat very fully. They recognised in gluten 
the three constituents described by Berzelius ; but the names 
they give indicate the more advanced, i. e. the comparative, 
stage which the inquiry had now reached. 
Wheat Proteids 
/ Albumine 
Gluten 
Fibrine [zymom] 
[glian] 
Casein e [myxon] 
Glutine 
Zymom, they, too, describe as fibrin ; and, like Mulder and 
Liebig, connect it closely with albumin, but point out that 
it is somewhat richer in nitrogen. The coagulated form of 
it however, with a smaller percentage of nitrogen, closely 
