588 FUNCTIONS OF ANIMALS. 



the most nutritious which contain all the three mixed in the re- 

 quisite proportions. None of the three are often exhibited by 

 nature in a state of purity. They are extricated from various 

 plants by artificial processes, more or less intricate and laborious. 

 Pure sugar was shown by Magendie not to be capable of sup- 

 porting the life of dogs. He fed them upon refined sugar. 

 They swallowed the food with avidity, yet they became lean and 

 thin, and exhibited all the symptoms of animals in a state of star- 

 vation. After some weeks, ulcers broke out in the cornea, first 

 of one eye and then in the other. These ulcers went on increas- 

 ing till they penetrated the cornea, and the liquors of the eye 

 were discharged by them. The dogs expired about the 32d day 

 in a state of complete exhaustion.* 



It would have been more satisfactory had this experiment 

 been made in a different manner. The dog is accustomed to 

 live entirely, or nearly so, on animal food. Hence the stomach 

 and intestines of these animal not being accustomed to vege- 

 table food, might not be able all at once to digest it. It is possible 

 that, had the change been induced sufficiently slowly, dogs might 

 at last be brought to live upon sugar. Yet it cannot be doubt- 

 ed, that had loaf bread been substituted for sugar, and that if 

 the dogs had been allowed to eat of it ad libitum, and at the 

 same time had been supplied with a sufficient quantity of water, 

 the change of diet, though it might not have been relished, and 

 though the animals might not have thriven on it, yet would not 

 have occasioned death. The juice of the sugar cane, in which 

 the sugar is mixed with mucilage and albumen, is a nutritive ar- 

 ticle of food. For it is said that the negroes in the West Indies 

 get fat from the unrestrained use of the juice during the season 

 in which raw sugar is manufactured. 



The animal matter, which seems to constitute the most nutri- 

 tious article of food, is a proper mixture of gelatin, albumen, and 

 fibrin, together with a certain portion of fat, as they exist in the 

 flesh of a well-fed ox or sheep. 



The use of animal food alone seems to have a tendency to 

 bring the body into an unhealthy state. As that dreadful dis- 

 ease, the sea-scurvy, is the usual consequence of it, at least when 

 the meat is salted, A restriction to vegetable food does not 

 seem by any means so injurious. Many persons who restricted 



* Ann. de Chim. et de Phys. iii. 66. 



