WASTE AND REPAIR. 179 



as due to forces analogous to those by which a crystal repro- 

 duces its lost apex, when placed in a solution like that from 

 which it was formed. In either case, a mass of units of a 

 given kind, shows a power of integrating with itself diffused 

 units of the same kind : the only difference being, that the 

 organic mass of units arranges the diffused units into special 

 compound forms, before integrating them with itself. In 

 the case of the crystal, this reintegration is ascribed to 

 polarity a power of whose nature we know nothing. What- 

 ever be its nature, however, it appears probable that the 

 power by which organs repair themselves from the nutritive 

 matters circulating through them, is of the same order. 



Go. That other kind of repair which shows itself in the 

 regeneration of lost members, is comprehensible only as an 

 e fleet of actions like those just referred to. The ability of 

 an organism to recomplete itself when one of its parts has 

 been cut off, is of the same order as the ability of an injured 

 crystal to recomplete itself. In either case, the newly^ assimi- 

 lated matter is so deposited as to restore the original outline. 

 And if in the case of the crystal, we say that the whole 

 aggregate exerts over its parts, a force which constrains the 

 newly-integrated atoms to take a certain definite form ; we 

 must in the case of the organism, assume an analogous force. 

 This is, in truth, not an hypothesis : it is nothing more than 

 a generalized expression of the facts. If when the leg of a 

 lizard has been amputated, there presently buds out the germ 

 of a new one, which, passing through phases of development 

 like those of the original leg, eventually assumes a like shape 

 and structure ; we assert nothing more than what we see, 

 when we assert that the organism as a whole exercises such 

 power over the newly- forming limb, as makes it a repetition 

 of its predecessor. If a leg is reproduced where there was a 

 leg, and a tail where there was a tail ; we have no alternative 

 but to conclude that the aggregate forces of the body, con- 

 trol the formative processes going on in each part. And on 



