438 KEEPING DOWN WEIGHT. 



the circulation and breathing, both of which functions are 

 engaged in the work of supplying the system with oxygen. 

 This gas and water are the two great purifiers of the body. 



Under ordinary conditions of life, most of the force 

 required for the production of movement and heat in the 

 body is obtained from the starch, sugar and fat in the food ; 

 albumen being mainly concerned in the repair of nitrogenous 

 tissue. Hence, exercise has little effect in increasing the 

 amount of nitrogenous waste during health ; but when 

 the reserve of fat becomes exhausted in cases of starva- 

 tion, the muscles and other nitrogenous tissues yield up their 

 force-producing elements with the result that they suffer from 

 a corresponding loss of substance, and the system becomes 

 more or less loaded with nitrogenous waste products, which 

 produce a depressing and hurtful influence on the bodily and 

 mental powers. These ill results are particularly well marked 

 in jockeys who trust more to sweats and Turkish baths than 

 to long-continued exercise for reducing weight. 



The mineral matter of the body consists of certain 

 substances which, like the phosphate of lime of bones, are 

 comparatively stable by reason of their being sparingly 

 soluble ; and others, like soda and potash, which, being 

 easily dissolved in water, rapidly pass out of the body, and 

 consequently require frequent replacement by means of 

 food. In the human and animal body, soda and potash play 

 a large part in nutrition, and are found in about equal 

 quantities ; but in plants, the percentage of potash far exceeds 

 that of soda. As a large excess of potash is hurtful to 

 health, and as it can be removed by soda, we find that 

 people who subsist chiefly on plant food, require it to be 

 supplemented by soda, which they usually obtain from common 

 salt. Hence the large use of salt among the potato-eating 

 peasantry of Ireland, and the rice-eating natives of India. 

 Human beings who live mostly on meat, have little or no 



