ITS RENOVATING INFLUENCE. 941 



young animals sleep more during the period of 

 rapid growth, than after they arrive at maturity. 

 Hence the remarkable activity and sprightliness 

 of children, after the term of infancy is passed, 

 and they have acquired the free use of their loco- 

 motive organs. In like manner, many persons 

 who have attained their full growth, enjoy better 

 health and spirits after great emaciation from 

 severe illness, and excessive medication, than for 

 several years before, provided no serious disor- 

 ganization has taken place. The reason of which 

 is, that after the body has been much reduced, 

 and the disease arrested, the process of renovation 

 by nutrition is more rapid than during an ordi- 

 nary state of health ; so that in respect to growth, 

 intellectual vivacity, and general excitability, 

 the individual returns for a time to the charming 

 condition of a new and youthful existence. 



It is maintained by Edward Johnson and other 

 Physiologists, that nutrition goes on only during 

 sleep. But I have proved that during the con- 

 traction of every muscle, and during every action 

 of every organ, there is an expenditure of sub- 

 stance and vital energy, in proportion to the ac- 

 tivity of each, and that, if not perpetually reno- 

 vated by a fresh supply of arterial blood and 

 vital heat, animal motion, and all the operations 

 of the nervous system, are extinguished in a few 

 minutes. So far is it from being true, that the 

 formative process goes on only during repose, or 



