390 Weismann's Theories — 



sentatives of each kind may be regarded as together really 

 forming but one self-segmented individual. 



Such organisms, as being the simplest and lowest, are 

 regarded by evolutionists as having been at first the only 

 living creatures in the world. The formation of multicellular 

 organisms, and the prevalence of death as we know it, the 

 Professor accounts for as follows: — From time to time some 

 unicellular organisms failed to subdivide themselves com- 

 pletely, and so, by degrees, came to consist of aggregations of 

 imperfectly divided, or at least of coherent cells. Some of 

 these were better able, on account of their state of aggrega- 

 tion, to support the struggle of life, and were therefore pre- 

 served. They were the more surely preserved, by reason of 

 the death and replacement of more or less of the individual 

 cells of which they were composed. He tells us (p. 60) : — 



* The replacement of the cells of the tissues must be more advan- 

 tageous for the functions of the whole organism than the unlimited 

 activity of the same cells, inasmuch as the power of single cells 

 would be much increased by these means. . . . The organism may 

 thus, figuratively speaking, venture to demand from the various 

 specific cells of tissues a greater amount of work than they are able 

 to bear.' 



Obviously an organism will be more vigorous and active 

 if the cells of which it is composed have adopted the principle 

 of ' the division of labour,' and mutually aid each other by 

 respectively dedicating themselves to one function exclu- 

 sively. But the consequence of such increased life must 

 ultimately be death, through a failure in such cells to repro- 

 duce themselves, and without an adequate supply of all, the 

 processes of hfe cannot be continued. Yet although a natural 

 mortahty, thus induced, must be fatal to the individual, it 

 must be all the better for the race or species, provided the 

 individuals only live long enough to sufficiently reproduce 

 their kind. 



Professor Weismann, however, affirms that the death of 



