84: THE PERrETUATION OF LIVIJN'G BEINGSj 



ganisms, and eventually to develop into the form of 

 one of its parents, as I explained in the first lecture. 

 These are the processes by which the perpetuation of 

 organic beings is secured. Why there should be the 

 two modes — why this re-invigoration should be re- 

 quired on the part of the female element we do not 

 know ; but it is most assuredly the fact, and it is pre- 

 sumable, that, however long the process of asexual 

 multiplication could be continued, — I say there is good 

 reason to believe that it would come to an end if a new 

 commencement were not obtained by a conjunction of 

 the two sexual elements. 



That character which is common to these two dis- 

 tinct processes is this, that, whether we consider the 

 reproduction, or perpetuation, or modification of or- 

 ganic beings as they take place asexually, or as they 

 may take place sexually, — in either case, I say, the off- 

 spring has a constant tendency to assume, speaking 

 generally, the character of the parent. As I said just 

 now, if you take a slip of a plant, and tend it with care, 

 it will eventually grow up and develop into a plant 

 like that from which it had sprung ; and this tendency 

 is so strong that, as gardeners know, this mode of mul- 

 tiplying by means of cuttings is the only secure mode 

 of propagating very many varieties of plants ; the pecu- 

 liarity of the primitive stock seems to be better pre- 

 served if you propagate it by means of a slip than if 

 you resort to the sexual mode. 



Again, in experiments upon the lower animals, such 

 as the polype, to which I have referred, it is most ex- 

 traordinary that, although cut up into various pieces, 

 each particular piece will grow up into the form of the 

 primitive stock ; the head, if separated, will reproduce 



