400 CHEMISTRY. 



is ground for doubt whether the distinction can be as 

 strictly carried out as is attempted by Liebig and others. 

 The reasons for this doubt will be noticed soon. 



566. Climate and Food. If the view above presented be 

 substantially correct, climate must have a great influence 

 upon the choice of food, the necessities of the case influ- 

 encing that choice to a considerable extent through the 

 instincts. Accordingly we find that oily and fatty food 

 is largely used by the inhabitants of the arctic regions, 

 from the great demand of the system for heat -making 

 food amid the surrounding cold. And provision is made 

 by the Creator for this want ; for the animals from which 

 the Esquimaux, the Greenlanders, etc., obtain their chief 

 nutriment as bears, seals, and whales are loaded with 

 fat, while there is but little of this substance in those 

 animals which furnish meat to the inhabitants of hot 

 climates. 



567. Warmth in Hibernation. It is observed that the 

 woodchuck and other warm-blooded animals that are in a 

 torpid state in the winter mouths are lean when they come 

 out of this state in the' spring, though they were very fat 

 when they went into it. This is because the fat is burned 

 up during the winter in maintaining the warmth requisite 

 for the continuance of life in this torpid state. So, also, in 

 disease, the fat previously accumulated in the system is 

 often used in the production of animal heat, the other 

 sources being in part cut off by the impaired ability to ap- 

 propriate food. 



568. Corpulency. In this state of body there is an ac- 

 cumulation to a larger degree than usual of fatty matters 

 in all quarters of the system. This is supposed to arise 

 from the fact that the heat-making food is provided in so 

 great amount that the oxygen introduced into the system 

 is far from being sufficient to burn it up. In this case the 



