in U77LITY OF DEA7H 67 



maintain the circulation of life upon the earth ; and to place a 

 higher value upon this than upon the continuance of vigorous, 

 joyful bodily existence must be difficult even for the most 

 consistent advocate of the principle of immediate utility."^ 



Death as an Adaptation 

 Immortality 



Weismann, we know, explains death itself as an advantage, 

 as an adaptation.^ 



The unicellular animals, the Protozoa, which multiply by 

 simple division, are, he says, immortal. The multicellular, 

 however, the Metazoa, are mortal. Originally the latter were 

 also immortal, but after they had differentiated their germ- 

 cells from their body-cells (somatic cells), so that reproduc- 

 tion could only be carried out through the former, they 

 became necessarily more and more imperfect, because they 

 were no longer able to repair the damages incurred during 

 life. Hence the utility of their death. 



The direct opposite of this is held by Gotte." According 

 to him, all animals are mortal, and reproduction is itself the 

 cause of death. Eeproduction in Protozoa is preceded by 

 encystation. In this condition the organism passes into a 

 non-living condition, from which it revives with renewed 

 youth and renewed life ; a similar condition occurs in the Qgg 

 of the Metazoa, during a certain period in which it forms an 

 unorganised, non-living body composed of organic substance. 

 The idea of " death " is here conceived as the stand-still of the 

 organic life of the whole — the idea of a corpse is not included. 



1 For botanical instances compare Askenaz, Beitrdge zur Kritih der Darwin- 

 schen Lehre, Leipzig, 1872. 



- A. Weismann, Ueher die Dauer des Lehens, an Address" delivered at the 

 Salzburg Naturalists' Congress, 1881 ; and Ueber Leben und Tod, eine biologische 

 Untersuchung, Jena, G. Fischer, 1884. 



^ Ueher den Ursjrrung des Todes, Hamburg, Voss, 1883. 



