392 Weismanfi s Theories — 



Even the males and females of the same species may 

 differ greatly as to duration of life. There are certain minute 

 parasites of bees the males of which only live for two or 

 three hours, while the females will continue to exist for over 

 a week. AVhatever may have determined the period during 

 which different kinds of multicellular animals live, there is 

 no doubt that they have sooner or later to die naturally, if 

 they escape all the various circumstances which occasion 

 accidental death. 



Nevertheless, just as the simplest unicellular organisms 

 produce, without dying, others like them — by means of a 

 process of self-division — so even the highest multicellular 

 organisms produce, without dying, others like them by 

 means of a process of self-division. For they separate off 

 those reproductive elements, which subsequently initiate a 

 new existence. 



Therefore it would seem that there must be an immortal, 

 corporeal part of every normal organism, however simple or 

 however complex may be that organism's structure. The 

 simplest creatures (as we have seen) are each immortal as 

 a whole ; but all the higher organisms are obviously and 

 imiversally. mortal as regards the visible mass of their 

 structure. 



Therefore every multicellular organism, from a Medusa 

 to a man, must consist of two parts : — (1) the great visible 

 mass of the body, which Professor Weismann speaks of as 

 the soinci ; and (2) some minute, ordinarily invisible, con- 

 stituent, and such a constituent is affirmed by the Professor 

 to exist and be transmitted, and this is named by him germ- 



According to his views, if we return in imagination to the 

 period when the first unicellular organisms were beginning 

 to cohere in more and more complex aggregations, we shall 

 see that, with the increasing division of labour amongst the 



