24 THE ORGANIC GROWTH OF THE LIVING WORLD SEC. 



BEPRODUCTIOX AS ORGANIC GROWTH 

 Sexual and Asexual Reproduction 



The peculiarity of reproduction as compared with individual 

 growth consists only in this, that parts separated from the 

 whole under certain conditions continue to grow. 



It is a fundamental property of the organism that as a 

 whole it wears out, that as a whole it must perish, die ; 

 another, that during its life it must constantly be nourished, 

 repaired, and in part renewed. It continues its race, it trans- 

 mits its life by division, or by separation of parts which go 

 on growing. 



Thus reproduction is a fundamental property of the 

 organism. 



The necessary repair and renewal finds its most complete 

 expression in sexual combination. For the beginnings of 

 sexual combination must be sought in conjugation 1 as it 

 occurs in lower organisms. And these beginnings indicate 

 that each of the organisms in question simply supplies some- 

 thing which makes up a deficiency in the condition of 

 nutrition in the other. 



Gradually from such conjugation, which originally took 

 place between two individuals sexually quite equivalent, 

 sexual separation has developed on the basis of the advantage 

 of division of labour, and the prevention of in-and-in breeding. 



The difference between sexual and asexual reproduction is 

 not more profound than this. 



Indeed, the union of egg and sperm is to be itself regarded 

 as a kind of conjugation, for egg and sperm are parts whicli 

 separate themselves in an asexual manner from the organism, 



1 Temporary contact of two unicellular, not externally dissimilar beings 

 obviously accompanied by exchange of material or permanent coalescence of two 

 such beings, in each case followed by reproduction. 



