1 88 LIFE AND HABIT. 



In the third it should show little or no sign of natural 

 decrease for a very long time. 



In the fourth there may be absolute and total steri- 

 lity, or sterility in regard to the particular organ, or a 

 scar which shall show that the memory of the wound 

 and of each step in the process of healing has been 

 remembered ; or there may be simply such disturbance 

 in the reproduced organ as shall show a confused 

 recollection of injury. There may be infinite gradations 

 between the first and last of these possibilities. 



I think that the facts, as given by Mr. Darwin 

 (" Plants and Animals," &c., vol. i. pp. 466-472, ed. 

 1875), will bear out the above to the satisfaction of the 

 reader. I can, however, only quote the following 

 passage : 



"... Brown Se'quard has bred during thirty years 

 many thousand guinea-pigs, . . . nor has he ever seen a 

 guinea-pig born without toes which was not the offspring 

 of parents 'which had gnawed off their awn toes, owing 

 to the sciatic nerve having been divided. Of this fact 

 thirteen instances were carefully recorded, and a greater 

 number were seen ; yet Brown Se'quard speaks of such 

 cases as among the rarer forms of inheritance. It is a 

 still more interesting fact ' that the sciatic nerve in 

 the congenitally toeless animal has inherited the power 

 of passing through all the different morbid states which 

 have occurred in one of its parents from the time of 

 division till after its reunion with the peripheric end. 

 It is not therefore the power of simply performing an 

 action which is inherited, but the power of performing 

 a whole series of actions in a certain order.' " 



