The Beginning and End of Life 389 



mann, can ever die a natural death. Like higher organisms, 

 however, they have to take nourishment, which leads to 

 growth. Such unicellular, generally spheroidal, organisms 

 absorb nourishment at their surface and grow, but the effect 

 of growth leads to a constantly increasing disproportion 

 between their very rapidly augmenting mass, which needs 

 to be nourished, and their much less rapidly expanding 

 nourishment-receiving surface. The consequence of this 

 must be either a state of stagnation, death, or — what really 

 ensues — a process of spontaneous division by means of which 

 a due balance of functions is for a time restored, followed by 

 reaugraentation of bulk and renewed division, and so on 

 continually. Obviously in a creature which divides into 

 two exactly similar halves, each half has an equal claim to 

 be considered as the continuation of the previously un- 

 divided whole, and this the more, since there is no evidence 

 of any cessation of life during the process. Certainly there 

 is no unequivocal corpse, and, as Professor Weismann 

 observes, there can be no death when there is no dead body. 

 But if the very living being of an organism is continued on 

 by means of the two halves into which it spontaneously 

 divides, then it must also be continued on into the subse- 

 quently and similarly divided portions of those halves them- 

 selves, and thus the being of the original undivided whole 

 must also be continued on into all the organisms to which it, 

 by its spontaneous division, gave rise. It therefore logically 

 follows not only that each kind of unicellular organism is, 

 accidents apart, immortal, but also that all the separate repre- 



that neither the structure of the nucleus nor that of the cell contents in 

 M'hich it is situated is simple, but that each contains a complex arrangement 

 of most delicate fibres. Cells multiply by spontaneous division, and in so 

 doing very singular and definite changes take place in the arrangement of 

 these fibres, the sum of such changes being denoted by the term karyokynesis. 

 The egg or ovum is a cell with its nucleus, the corresponding male project 

 is but the nucleus of a cell with which a portion of cell contents is probably 

 conjoined. 



