

FOOD. 211 



in many epitheliums : in that of the cerebral ventricles are 

 found white granules, some of which, in their behavior 

 with the reagents, resemble amylaceous matter, and others 

 dextrine ; sugar also exists in the muscles and accumulates 

 when they are not in action (as after long repose ; after 

 section of the motor nerves, and in the muscles of the foetus), 

 (Rouget). The integument of the non-vertebrated animals 

 is formed of a glycogenous substance: this is the chitine of 

 insects, the tunicine of the tunicata (animal cellulose), (Carl 

 Schmidt). These substances are transformed into sugar by 

 boiling with potash (Berthelot, Rouget). All these classes 

 of alimentary substances become capable of being absorbed 

 by contact with the digestive organs. 



4. The last class of alimentary substances is the fats ; 

 these do not require to be digested, in the proper sense of 

 the word; that is to say, the digestive juices produce no 

 change in them ; the fats are unchanged. They may, even, 

 be absorbed by other surfaces than those of the digestive 

 organs, as by the skin, for instance ; we know that if fatty 

 substances be rubbed on the skin, they will penetrate the 

 epidermis : this is the only possible mode of nutrition by 

 means of the external integument. The fatty substances are 

 found in both the animal and vegetable kingdom. 



Thus we see that nourishment may be derived, almost 

 indifferently, from either the animal or vegetable kingdom : 

 the amylaceous, glycogenous matters, forming almost the 

 essential element of vegetables, are also found in animal 

 products ; thus we know that some savage tribes make fer- 

 mented liquors (alcohol) with the sugar found in mares' 

 milk. We have an instance, on the other hand, of an aliment 

 which is apparently and essentially animal, though found 

 in the vegetable kingdom : in the cheese which the Chinese 

 make from legumine (caseine) derived from the fruit of legu- 

 minous plants. 



It is especially important, however, to remark that the 

 property of forming some of these substances does not belong 

 to vegetables only, to the exclusion of animals : the forma- 

 tion of albuminoid substances evidently belongs to both 

 kingdoms; the discovery of animal glycogeny (C. Bernard) 

 proves that animals, as well as vegetables, can and do nat- 

 urally form amylaceous substances, and the same is true 

 with regard to fatty substances : we owe to experiments by 

 F. Huber, Milne-Edwards, and Dumas, the knowledge of the 

 fact that bees, fed exclusively on sugar, still possess the 



