655 



exhaustion ? The state of perfect health enjoy- 

 ed by the Otomacs during the time when they 

 use little muscular exercise, and are subjected 

 to so extraordinary a regimen, is a phenomenon 

 difficult to be explained. It can be attributed 

 only to a habit, prolonged from generation to 

 generation. The structure of the digestive ap- 

 paratus differs much in animals, that feed ex- 

 clusively on flesh or on seeds ; it is even proba- 

 ble, that the gastric juice changes it's nature, 

 according as it is employed in effecting the 

 digestion of animal or vegetable substances ; yet 

 we are able gradually to change the regimen of 

 herbivorous and carnivorous animals, to feed 

 the former with flesh, and the latter with vege- 

 tables. Man can accustom himself to an extra- 

 ordinary abstinence, and find it but little pain- 

 ful, if he employ tonic or stimulating substances 

 (various drugs, small quantities of opium, betel, 

 tobacco, leaves of coca) ; or if he supply his 

 stomach from time to time with earthy, insipid 

 substances, that are not in themselves fit for 

 nutrition. Like man in a savage state, some 

 animals also, when pressed by hunger in winter, 

 swallow clay or friable steatites ; such are the 

 wolves in the north-east of Europe, the rein- 

 deer, and, according to the testimony of Mr. 

 Patrin, the kids in Siberia. The Russian hunt- 

 ers on the banks of the Jenisey and the Amour 

 use a clayey matter, which they call rock butter 9 



