130 FOOD. 



protein that cannot be tested by any method now at our command, 

 differences which would explain the almost universal preference 

 for some animal food in the diet. From our present knowledge it 

 would seem that a mixed diet of both animal and vegetable food 

 is the best and most practicable for the vast majority of people." 



In Physiological Economy in Nutrition, (p. 139), Prof. Chit- 

 tenden says, " Man is an omnivorous animal and Nature evidently 

 never intended him to subsist solely on a cereal diet, or on any 

 specific form of food to the exclusion of all others. . . . Vege- 

 tarianism may have its virtues, as too great indulgence in flesh 

 foods may have its serious side, but there would seem to be no 

 sound physiological reason for the complete exclusion of any one 

 class of food-stuffs, under ordinary conditions of life." 



From the above consideration of the subject we learn that a 

 proper diet must contain not only the various food-stuffs, but must 

 contain them in the proper proportion. These proportions will 

 vary considerably according to the age of the individual and his 

 occupation, and also according to the climate in which he lives. 

 A glance at the chemical composition of milk, which is the sole 

 food of the infant, shows that the amount of proteids and fats is 

 very much above that in the food of the adult. 



Another factor to determine the nutritive value of any food is 

 its digestibility. The chemical analysis of cheese would place it 

 high among the foods, but experience shows that its constitution 

 is such as not readily to permit the action of the digestive fluids, 

 and its availability as a food is therefore low. 



The following table represents a daily diet as recommended 

 by two authorities : 



Moleschott. . Ranke. 



Proteids 120 grams. ' 100 grams. 



Fats 90 " 100 " 



Carbohydrates 333 " 250 " 



Ranke's diet, Avhich he regarded as sufficient for himself, weigh- 

 ing 74 kilos, corresponds to 230 grams of carbon and 14 grams 

 of nitrogen. 



While such diets as these are undoubtedly " adequate," they 

 are, after all, to be regarded as general averages only, to be varied 

 according to the needs of those for whose maintenance provision 

 is to be made. Thus, Yoit (p. 138) would supply to a man weigh- 

 ing 70 to 75 kilos, and working ten hours a day, 118 grams of 

 proteid, 56 grams of fat, and 500 grams of carbohydrates : this 

 diet would give him 328 grams of carbon and 18.3 grams of nitro- 

 gen, and would have a total fuel-value of 3000 large calories. 



Stewart regards 500 grams of bread and 250 grams of lean 

 meat as a fair quantity for a man fit for hard work. To this 

 he adds 500 grams of milk, 75 grams of oatmeal in the form of 

 porridge, 30 grams of butter, 30 grams of fat either in the meat 

 or otherwise, and 450 grams of potatoes. From this would be 



