112 LIFE AND DEATH. [III. 



in its duration, not because it was contrary to its very nature to 

 be unlimited, but because an unlimited persistence of the indi- 

 vidual would be a luxury without a purpose. Among uni- 

 cellular organisms natural death was impossible, because the 

 reproductive cell and the individual were one and the same : 

 among multicellular animals it was possible, and we see that it 

 has arisen. 



Natural death appeared to me to be explicable on the prin- 

 ciple of utility, as an adaptation. 



These opinions, to which I shall return in greater detail in 

 a later part of this paper, have been opposed by Gotte \ who 

 does not attribute death to utility, but considers it to be a neces- 

 sity inherent in life itself. He considers that it occurs not only 

 in the Metazoa or multicellular animals, but also in unicellular 

 forms of life, where it is represented by the process of encyst- 

 ment, which is to be regarded as the death of the individual. 

 This encystment is a process of rejuvenescence, which, after 

 a longer or shorter interval, interrupts multiplication by means 

 of fission. According to Gotte, this process of rejuvenescence 

 consists in the dissolution of the specific structure of the in- 

 dividual, or in the retrogression of the individual to a form 

 of organic matter which is no longer living but which is com- 

 parable to the yolk of an ^%g. This matter is, by means of its 

 internal energy, and in consequence of the law of growth which 

 is inherent in its constitution, enabled to give rise to a new in- 

 dividual of the same species. Furthermore, the process of 

 rejuvenescence among unicellular beings corresponds to the 

 formation of germs in the higher organisms. The phenomena 

 of death were transmitted by heredity from the unicellular 

 forms to the Metazoa when they arose. Death does not there- 

 fore appear for the first time in the Metazoa, but it is an ex- 

 tremely ancient process which ' goes back to the first origin of 

 organic beings' (1. c, p. 8i). 



It is obvious, from this short resume, that Gotte's view is 

 totally opposed to mine. Inasmuch as only one of these views 

 can be fundamentally right, it is worth while to compare the 

 two ; and although w^e cannot at present hope to explain the 

 ultimate physiological processes which involve life and death, 

 I think nevertheless that it is quite possible to arrive at definite 

 ^ 'Ueber den Ursprung desTodes,' Hamburg and Leipzig, 1883. 



