26 THE DURATION OF LIFE. [I. 



constructed, contain within themselves the germs of death. 

 The question however arises as to how this has come to pass ; 

 and I reply that death is to be looked upon as an occurrence 

 which is advantageous to the species as a concession to the 

 outer conditions of life, and not as an absolute necessity, essen- 

 tially inherent in life itself. 



Death, that is the end of life, is by no means, as is usuall}^ 

 assumed, an attribute of all organisms. An immense number 

 of low organisms do not die, although they are easily destroyed, 

 being killed by heat, poisons, etc. As long, however, as those 

 conditions which are necessary for their life are fulfilled, they 

 continue to live, and they thus carry the potentiality of unending 

 life in themselves. I am speaking not only of the Amoebae and 

 the low unicellular Algae, but also of far more highly organized 

 unicellular animals, such as the Infusoria, 



. The process of fission in the Amoeba has been recently much 

 discussed, and I am well aware that the life of the individual is 

 generally believed to come to an end with the division which 

 gives rise to two new individuals, as if death and reproduction 

 were the same thing. But this process cannot be truly called 

 death. Where is the dead body ? what is it that dies ? Nothing 

 dies ; the body of the animal only divides into two similar 

 parts, possessing the same constitution. Each of these parts 

 is exactly like its parent, lives in the same manner, and finally 

 also divides into two halves. As far as these organisms are 

 concerned, death can only be spoken of in the most figurative 

 sense. 



There are no grounds for the assumption that the two halves 

 of an Amoeba are differently constituted internally, so that after 

 a time one of them will die while the other continues to live. 

 Such an idea is disproved by a recently discovered fact. It has 

 been noticed in Euglypha (one of the Foraminifera) and in other 

 low animals of the same group, that when division is almost 

 complete, and the two halves are only connected by a short 

 strand, the protoplasm of both parts begins to circulate, and for 

 some time passes backwards and forwards between the two 

 halves. A complete mingling of the whole substance of the 

 animal and a resulting identity in the constitution of each half 

 is thus brought about before the final separation \ 



^ See Appendix, note lo, p. 65. 



