PROCESS OF REGENERATION 



149 



fifteen minutes, and the number of pieces completely disintegrated 

 recorded. 



The general result of experiments of this kind is that the rate 

 of metabolism of anterior pieces falls rapidly after cutting, and 

 rises again, so that within four days, it has reached the normal 

 rate. In posterior pieces, the rate stays up longer after cutting, 

 then falls to a greater extent, and remains low for a longer period 

 of time. Further experiments show that it begins to rise by the 



TABLE G 

 Suseeptibiliiy of shurt poslerior piece ah to K.CN-g^^^al various times after section 



sixth day. Eventually the rate of metabolism of all regener- 

 ating pieces becomes much higher than their original rate as 

 parts of the organism; rejuvenation thus occurs as a result of 

 regeneration. 



The rate of metabolism, then, of anterior pieces of Lumbriculus 

 is low during the period that the head is determined as normal; 

 and these pieces give rise to a high percentage of normal heads. 

 On the contrary, the rate of metabolism of posterior pieces is 



