79 6 THE POPULAR SCIENCE MONTHLY. 



the latter to furnish the necessary nervous impulses to the digest- 

 ive organs and the tissues in every part of the organism : for it is 

 not enough that food be digested in the ordinary sense ; it must 

 also be built up into the tissues, a process depending, as we shall 

 endeavor to show later, on the nervous system. 



The " gastronomic art " has, therefore, become of great impor- 

 tance. It is as yet more of an art than a science ; the cook has out- 

 stripped the physiologist, if not the chemist also, in this direction. 



We can not explain fully why food prepared by certain meth- 

 ods and served in courses of a certain established order is so suited 

 to refined man. A part is known, but a great deal remains to be 

 discovered. We may, however, notice a few points of importance 

 in regard to the preparation of food. 



It is now well established by experience that "animals kept in 

 confinement must have, in order to escape disease and attain the 

 best results on the whole, a diet which not only imitates that of 

 the corresponding wild forms generally, but even in details, it may 

 be, with altered proportions or added constituents, in consequence 

 of the difference in the environment. To illustrate : poultry can 

 not be kept healthy confined in a shed without sand, gravel, old 

 mortar, or some similar preparation ; indeed, for the best results 

 they must have green food also, as lettuce, cabbage, chopped 

 green clover, grass, etc. They do not require as much food as if 

 they had the exercise afforded by running hither and thither over 

 a large field. We have chosen this example because it is not com- 

 monly recognized that our domesticated birds have been so modi- 

 fied that special study must be made of the environment in all 

 cases if they are not to degenerate. The facts in regard to horned 

 cattle, horses, and dogs are perhaps better known. 



But all these instances are simple as compared with man. 

 The lower mammals can live and flourish with comparatively 

 little change of diet ; not so man. He demands food not only dis- 

 similar in its actual grosser nature, but differently prepared. In 

 a word, for the efferent nervous impulses, on which the digestive 

 processes depend, to be properly supplied, it has become necessary 

 that a variety of afferent impulses (through eye, ear, nose, palate) 

 reach the nervous centers, attuning them to harmony, so that they 

 shall act, yet not interfere with one another. 



Cooking greatly alters the chemical composition, the mechani- 

 cal condition, and, in consequence, the flavor, the digestibility, and 

 the nutritive value of foods. To illustrate : meat in its raw con- 

 dition would present mechanical difficulties, the digestive fluids 

 permeating it less completely ; an obstacle, however, of far greater 

 magnitude in the case of most vegetable foods. By cooking, cer- 

 tain chemical compounds are replaced by others, while some may 

 be wholly removed. As a rule, boiling is not a good form of pre- 



