Chapter XIV 

 THE REACTION TO FOOD 



Elmer V. McCollum 



PHILOSOPHERS in all ages have given thought to the 

 nature of foods and of nutritional processes. Spallan- 

 zani ( 1 729-1 799) who occupied himself with many 

 experiments on the digestion of foods, was of the opinion 

 that there was but one kind of food or ahment. This view 

 had seemed satisfactory to some early Greek philosophers, 

 but by the beginning of the nineteenth century the eminent 

 French physiologist Magendie reached the conclusion that 

 there are several kinds of nutrient principles in a chemical 

 sense. Even as late as 1835, when Dr. Wilham Beaumont, 

 a surgeon in the U. S. Army, was writing about his famous 

 experiments on digestion conducted with Alexis St. Martin 

 as a subject, he expressed the view that there wais but one 

 kind of nutrient principle or aliment. He beheved that this 

 ahment was contained in all the many varieties of foodstuffs 

 consumed by man and animals and that the process of 

 nutrition involved dissolving out this principle by the 

 digestive juices and converting it into a salt-like derivative 

 of a substance which he called gastrite, forming gastrite of 

 ahment. This he beheved with shght modifications entered 

 the blood and served with little change for the upbuilding or 

 repair of tissues. 



During the nineteenth century much knowledge accumu- 

 lated concerning the nature of proteins, carbohydrates, 

 fats and the inorganic or mineral constituents of foodstuffs. 

 About 1865 a method was formulated and adopted by the 

 Association of Agricultural Chemists as official for the 

 analysis of foods. In this method proteins, digestible car- 

 bohydrates, cellulose, fats and mineral constituents were 

 separately estimated with a fair degree of accuracy. The 

 behef became almost universal among students of nutrition 

 that these four classes of nutrients were all that were necessary 

 for the support of animal nutrition. 



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