90 



THE PROTEINS OF THE WHEAT KERNEL. 

 Table 18. Protein of the wheat kernel soluble only in dilute acids and alkalis. 



There can be no doubt that the earlier analyses of this protein, with the 

 exception of those made by Ritthausen and Chittenden & Smith, are incor- 

 rect, for the substance analyzed contained a large part of the impurities of 

 the gluten, since after extraction with alcohol the residue was not dissolved 

 in any solvent, and the starch, bran, etc., contained in it filtered off. Ritt- 

 hausen' s figures are the average of two analyses of preparations obtained 

 from solutions in 0.2 per cent potassium-hydroxide water which had been 

 filtered, one perfectly clear, giving a product containing 17.21 per cent N, 

 the other very nearly clear and containing 17.08 per cent N. 



It is evident that the alkaline solution of the gluten that has previously 

 been extracted with cold dilute alcohol contains something which requires 

 filtration through very dense paper to effect its separation. Wheat gluten 

 contains a considerable amount of phytocholesterin and lecithin, together with 

 fat, and it is probable that all these bodies are held suspended in the solution 

 of the dissolved protein as an emulsion, and can only be removed by pre- 

 cipitating the first solution in potassium-hydroxide water, extracting the 

 precipitate with alcohol and ether, redissolving, and filtering the resulting 

 solution perfectly clear. The first alkaline solution before precipitating and 

 extracting with alcohol and ether can not be filtered, as it either passes 

 through turbid or does not run through at all. 



On the ground of priority and the fact that the relations to animal proteins 

 which gave rise to the various names subsequently applied to this body have 



