94 Food-Grains of India. 



All these estimations are based upon actual determinations 

 of nitrogen, made either by Dumas's absolute nitrogen method 

 or by the easier process of combustion with soda-lime, the 

 percentage of nitrogen obtained being then multiplied by 

 6'3. Many higher figures have been published, but these, 

 so far as I can learn, have been obtained by a most 

 misleading and incorrect method, namely, the weighing of 

 the so-called "gluten" which is left after washing out the 

 starch from a prepared dough by means of water. The gluten 

 so separated is often largely contaminated with starch as well 

 as with wheat-oil and wheat-fibre, while such contamination is 

 too variable to admit of being allowed for. It is greatly to be 

 regretted that many works on food-materials and dietetics should 

 be disfigured by erroneous figures arising from the use of this 

 unsafe process. As to the maximum percentage of albuminoids 

 present in Indian wheat it is probable that it really does some- 

 times exceed 167, the above-given number, but as yet I have no 

 actual determinations confirmatory of this view. 



Much of the Indian wheat, whether white or red, has that 

 translucent aspect which generally indicates a high percentage of 

 albuminoids. In 1867 ("Practice with Science," i., pp. loi-iii, 

 345-348), I pointed out some of the chief relationships between the 

 aspect, density, weight per bushel, productiveness, and chemical 

 composition of wheat-grain, showing more particularly that the 

 exclusion of a small proportion of the lightest of the grains in a 

 seed-corn tells very favourably upon the yield, and also that there is 

 a very intimate connection between the translucency or horny cha- 

 racter of a grain and a high percentage of albuminoids ; and, again, 

 between the softness and opacity of a grain and a high percentage 

 " ' of starch. Such differences in the composition of wheat-grain 

 show themselves not merely in different varieties of wheat, but 

 even in the same variety of wheat when it has been grown under 

 different conditions of climate or season. Even in the grains from 

 a single ear similar differences may often be seen — analysis show- 

 ing sometimes 3 or 4 per cent, more albuminoids in some of such 

 grains than in others Often a single grain will be partly horny 



