FOOD. 115 



pensed with for a few days, but not indefinitely. The experiment has 

 often been tried, in the treatment of diabetes, of confining the patient 

 to a strictly animal diet. It has been invariably found that, if this regi- 

 men be continued for some weeks, the desire for vegetable food becomes 

 so imperative that the plan of treatment is unavoidably abandoned. 



A similar question has arisen with regard to the oleaginous matters. 

 Are these substances indispensable as ingredients of the food, or may 

 they be replaced by other proximate principles, such as starch or sugar ? 

 It has already been seen, from the experiments of Boussingault and 

 others, that a certain amount of fat is produced in the body over and 

 above that which is taken with the food ; and it appears also that a 

 regimen abounding in saccharine substances is favorable to the produc- 

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

 the production of fat may be derived, under these circumstances, either 

 directly or indirectly from saccharine matters. But saccharine matters 

 alone are not sufficient. Dumas and Milne-Edwards 1 found that bees, 

 fed on pure sugar, soon cease to work, and sometimes perish in con- 

 siderable numbers ; but if fed with honey, which contains some waxy 

 and other matters beside the sugar, the} r thrive upon it ; and produce, 

 in a given time, a much larger quantity of fat than was contained in 

 the whole supply of food. 



The same thing was established by Boussingault with regard to 

 starchy matters. He found that in fattening pigs, though the quantity 

 of fat accumulated by the animal considerably exceeded that contained 

 in the food, yet fat must enter to some extent into the composition of 

 the food in order to maintain the animal in good condition ; for pigs, 

 fed on boiled potatoes alone (an article abounding in starch but nearly 

 destitute of oily matter), fattened slowly and with difficulty ; while 

 those fed on potatoes mixed with a greasy fluid fattened readily, and 

 accumulated much more fat than was contained in the food. 



The apparent discrepancy between these facts may be easily explained, 

 when we recollect that, in order that an animal become fattened, it must 

 be supplied not only with the materials of the fat itself, but also with 

 everything else necessary to maintain the body in a healthy condition. 

 Oleaginous matter is one of these necessary substances. The fats taken 

 in with the food are not simply introduced into the body and deposited 

 unchanged. On the contrary, they are altered and used up in the pro- 

 cess of digestion and nutrition ; while the fats which appear as con- 

 stituents of the tissues are, in great part, of new formation, and are 

 produced from materials derived, perhaps, from a variety of sources. 



It is certain, then, that either one or the other of these two groups of 

 substances, saccharine or oleaginous, must enter into the composition 

 of the food ; and furthermore, that, though oily matter may sometimes 

 be produced in the body from the sugars, it is also necessary for perfect 

 nutrition that fat be supplied, under its own form, with the food. For 



1 Annales de Chimie et de Physique, 3d series, tome xiv. p. 400. 



