i^o PLANT PRODUCTS 



Wheat grown on irrigated land contains less nitrogen 

 than that grown on non-irrigated land, but this may quite 

 possibly be only part of the general principle that vigorous 

 growth results in the production of carbohydrates. 



Crude gluten from wheat amounts to 8 to 15 per cent, of 

 the wheat flour, No. i Manitoba wheat flour containing over 

 13 per cent, and English flours under 10 per cent. 



Crude gluten dried at a low temperature is used to make 

 biscuits for diabetes patients. 



Leguminous Proteins. — Many of the leguminous seeds, 

 such as peas, beans, and lentils, contain relatively much 

 protein soluble in water, which, after the addition of acetic 

 and carbonic acids, is largely precipitated, but is soluble 

 again in concentrated saline solutions, and is generally 

 considered as a globulin. It was formerly supposed that 

 many proteins were strong acids in all but name, and formed 

 salts with bases, on which grounds many of the proteins 

 were described in older literature as caseins. The legumin 

 from peas and beans was long regarded as a protein of strong 

 acid character. Recent studies have, however, shown that 

 the solubility caused by the addition of large quantities 

 of alkali is not due to this. lyCgumin in the free state is 

 soluble with water, but when combined with acids forms 

 salts which are insoluble, and the idea that legumin is a strong 

 acid in a free state, but forming salts, is no longer a tenable 

 hypothesis. Many of the leguminous seeds, when freshly 

 ground, yield water extract, from which the protein separates 

 by the development of acid. The separation can quickly 

 be effected by adding a small quantity of any common acid. 

 IvCgumin, previously dissolved in dilute sodium hydrate, 

 is not precipitated by adding enough acid to combine with 

 all the alkali that has been added, but very little more acid 

 forms an insoluble salt of legumin. Still further addition 

 of acid, however, suffices to redissolve the precipitate. 

 The leguminous proteins are usually particularly rich in 

 nitrogen, and yield on hydrolysis a large proportion of 

 arginine. 



Vicilin, from peas, is characterized by the small amount 



