120 PHYSIOLOGICAL CHEMISTRY. 



than those deprived of both solids and liquids. Sodium chloride, also, 

 is usually added to the food in considerable quantity, and requires 

 to be supplied as a condiment with some regularity ; while the remain- 

 ing inorganic materials, such as calcareous salts, and the alkaline phos- 

 phates and sulphates, occur naturally in sufficient quantity in most 

 articles of food. 



The entire quantity of mineral substances discharged daily by a 

 healthy adult, by both the urine and perspiration, averages as follows : 



QUANTITY OF MINERAL MATTERS DISCHARGED PER DAT. 

 Sodium and potassium chlorides . . . 15.0 grammes. 

 Calcareous and magnesian phosphates . . 1.0 " 



Sodium and potassium phosphates ... 4.5 " 

 Sodium and potassium sulphates ... 4.0 " 



24^5" " 



According to the average dietaries for adults, in full health, collected 

 by Playfair,* about 20 grammes of mineral matter are daily introduced 

 with the food. The remainder is accounted for by the phosphates and 

 sulphates formed within the system as above described. 



Non-Nitrogenous Organic Ingredients of the Food. 



These substances, so far as they enter into the composition of the 

 food, are divided into two natural groups, namely,, carbohydrates, 

 including starch and sugar, and fats, including all varieties of ole- 

 aginous matter. Since starch is converted into glucose in the digestive 

 process, these two substances may be regarded as having the same 

 nutritive value. They occur abundantly only in vegetable products, 

 and the herbivorous animals alone consume them in considerable 

 quantity in their food; while the carnivora obtain a comparatively 

 small proportion of glycogen and glucose in the tissues and juices 

 upon which they feed. For man the natural diet is a mixed regimen 

 of animal and vegetable food ; and it is invariably found that a 

 continued privation of vegetable substances produces a craving for 

 carbohydrates, which indicates their necessity for healthy nutrition. 



A similar question has arisen with regard to oleaginous matters. 

 Are these substances indispensable in the food, or may they be replaced 

 by starch or sugar ? It has already been seen, from the experiments 

 of Boussingault, that a certain amount of fat is produced in the body 

 over and above that taken with the food ; and it appears also that 

 a regimen abounding in saccharine substances is favorable to the 

 production of fat. It is probable, therefore, that the materials for the 

 production of fat may be derived, either directly or indirectly, from 

 saccharine matters. But saccharine matters alone are not sufficient. 

 Dumas and Milne-Ed war dsf found that bees, fed on pure sugar, soon 

 cease to work, and sometimes perish in considerable numbers ; but if 



* London Chemical News, May 12, 1865. 



f Annales de Chiraie et de Physique, 3d series, tome xiv., p. 400. 



