300 PHYSIOLOGY. 



course he required nothing to supply any loss, but how the 

 vital principle was preserved for such a length of time, is a 

 mystery not easy to be explained. 



7. \phe blood contains all the materials of nutrition.) The 

 process by which the food is changed into blood has been al- 

 ready explained. As it goes the round of circulation, the 

 nutrient capillary vessels select and secrete those parts which 

 are similar to the nature of the structure, and the other por- 

 tions pass on ; so that every tissue takes up and converts to 

 its own use the very principles which it requires for its 

 growth ; or in other words, as the vital current approaches 

 each organ, the particles appropriate to it, feel its attractive 

 force ; obey it ; quit the stream ; mingle with the substance 

 of its tissue, and are changed into its own true and proper 

 nature. 



8. (Before the body has attained its full growth, \he func- 

 tion or nutrition is very active ; a large amount of food is 

 taken, being not only sufficient to supply the place of what 

 is lost by the action of the absorbents, but also to contribute 

 to the growth of the body. In middle age, nutrition and ab- 

 sorption are more equal ; but (In old age the absorbents are 

 more active than the nutrient vessels); /the size consequently 

 diminishes ; the parts grow weaker ; the bones more brittle ; 

 the body bends forward ; and every function exhibits marks 

 of decay and dissolution) 



9. A few years ago, a man by the name of Calvin Edson, 

 of Vermont, commonly called the living skeleton, exhibited 

 himself through the country for money. From having been 

 a large man, he had wasted away by degrees, so that instead 

 of his usual weight, he weighed but sixty pounds. He had 

 been gradually losing flesh for eighteen years ; and he attri- 

 buted it to having taken cold from sleeping on the ground. 

 This emaciation was owing to the absorbent vessels being 

 more active than those of nutrition ; whatever may have 

 been the cause of the loss of balance. 



