consumes both will not assimilate the plastic matters so well as if they were endowed with a pleasant flavor. In seeds and other perfectly matured vegetable structures, the flesh-formers may exist in different degrees of availability. The nitrogen of the _testa_, or covering of the seeds, will hardly be so assimilable as that which exists in their cotyledons. The solubility of the flesh-formers--provided they be highly elaborated--is a very good criterion of their nutritive power. In linseed the muscle-forming substances are more soluble than in linseed-cake--the heat which is generally employed in the extraction of oil from linseed rendering the plastic materials of the resultant _cake_ less soluble, and diminishing thereby their digestibility, as practice has proved. From the considerations which I have now entered into, it is obvious that the chemical analysis of food substances as generally performed, though of great utility, does not afford strictly accurate information as to their commercial value, and still less reliable in relation to their nutritive power. At the same time, they as clearly establish the feasibility of analyses being _made_ whereby the money value of feeding-stuffs may be estimated with tolerable exactitude. Let the chemist determine the presence and relative amounts of the ingredients of food-substances, and--if it be possible so to do with a degree of exactness that would render the results useful--place on each a money value. This done, let the physiologist and the feeder combine the food in such proportions as they may find best adapted to the nature, age, and condition of the animal to be fed.