IDENTITY OF PARENT AND OFFSPRING. 207 



by self-division, the original organism and the sub- 

 divided halves are related to each other by physical 

 identity. 



3. In a self-divided organism, physical identity is 

 transmitted by hereditary descent. 



Here begins, but here by no means, as Hackel 

 thinks, ends, the explanation of the law that like 

 breeds like. Two yet greater facts are equally de- 

 monstrable with the three already mentioned : 



4. The co-ordinating powers governing the move- 

 ments of the two halves are also identical. 



5. The co-ordinating power is therefore transmit- 

 ted in hereditary descent. 



In our subdivided organism here [referring to the 

 blackboard], each half goes on acting as the parent 

 did. Each takes up nutriment, and enlarges, and 

 finally divides, as did its parent. These movements 

 must have a cause. The laws of the movements are 

 identical with the laws of the original organism. 

 The co-ordinating power which we have proved to 

 lie behind all the movements of organisms, we know, 

 therefore, is transmitted here. Its effects are visibly 

 the same here as they were there. The cycle of life 

 through which that subdivided half passes is the 

 same as that through which the parent passed. The 

 co-ordinating power goes over; the physical power 

 goes over. 



6. Between the parent and the germ of the child, 

 there exists, therefore, a double identit}', the, one 

 physical, and the other not physical ; the one mate- 

 rial, and the other not material. 



