FAT HOW FORMED. 85 



not given out in the free state, because it meets in the 

 organism with substances possessing the property of en- 

 tering into combination with it. In fact, it is given out 

 in the same forms as that which is absorbed from the 

 atmosphere by the skin and lungs. 



It is easy to see, from the above considerations, that 

 a very remarkable connexion exists between the forma- 

 tion of fat and the respiratory process. 



XVII. The abnormal condition, which causes the 

 deposit of fat in the animal body, depends, as was for- 

 merly stated, on a disproportion between the quantity 

 of carbon in the food and that of oxygen absorbed by 

 the skin and lungs. In the normal condition, the quan- 

 tity of carbon given out is exactly equal to that which 

 is taken in the food, and the body acquires no increase 

 of weight from the accumulation of substances contain- 

 ing much carbon and no nitrogen. 



If we increase the supply of highly carbonized food, 

 then the normal state can only be preserved on the con- 

 dition that, by exercise and labor, the waste of the 

 body is increased, and the supply of oxygen augmented 

 in the same proportion. 



The production of fat is always a consequence of 

 a deficient supply of oxygen, for oxygen is absolutely 

 indispensable for the dissipation of the excess of carbon 

 in the food. This excess of carbon, deposited in the 

 form of fat, is never seen in the Bedouin or in the Arab 

 of the desert, who exhibits with pride to the traveller 

 his lean, muscular, sinewy limbs, altogether free from 

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