EXPLANATION OF DEA TH 



principal function is to ensure the maintenance of organic 

 life by favouring reproduction, by sheltering the germ-cells 

 till their maturity, and in order to deposit them repeatedly ; 

 further, by the dispersal of the same in space, by incubation 

 in the widest sense, and so on. Further, it has the function 

 of strengthening the power of endurance of the species by 

 the inheritance of acquired characters. 



" Eeproduction is unending growth. Not reproduction is 

 the essential cause of death, but the differentiation of the 

 constituent parts of the soma resulting from division of 

 labour, in the last result division of labour itself, to which the 

 soma owes its very existence : the germ-cells alone are still 

 individually complete elementary organisms, and as such 

 retain still the general complete combination of matter which 

 in them as in Protozoa ensures endless growth. To the soma 

 such growth is impossible because these fundamental condi- 

 tions in it are wanting ; it dies in consequence of the exhaus- 

 tion of the organs. 



"Separation of the sexes is likewise due to division of 

 labour, and sexual reproduction finds its explanation in this 

 very necessity of the complete combination referred to as a 

 condition of endless growth. And thus at the same time 

 parthenogenesis would explain itself." 



This conception is in some measure completed and 

 developed in the preceding and following pages. I have to 

 add here at once : there are also Metazoa whose bodies (soma), 

 in that they divide or multiply by budding, maybe immortal. 

 Amongst these are instances in which division of labour in 

 the organisation has not yet attained any considerable 

 development (many Zoophytes, e.g. Hydra), and others in 

 which the body consists of equivalent parts, into which it 

 may separate (e.g. Annelids, like Nais). In both cases such a 

 reproduction (possibly unending) of the soma without the aid 

 of the germ-cells can only occur because the parts have all 



