146 LIFE AND DEATH. [III. 



latter then die with the soma. But this does not make any 

 difference to their potential immortality, any more than it 

 modifies the scientific conception of a corpse. The idea of 

 natural death involves that of a corpse, which consists of the 

 soma, and when the latter happens to contain reproductive 

 cells, these do not succumb to a natural death, which can never 

 apply to them, but to an accidental death. They are killed by 

 the death of the soma just as they might be killed by any other 

 accidental cause of death. 



The scientific conception of a corpse is not affected, whether 

 the dead som,a remains whole for some time, or falls to pieces 

 at once. I cannot therefore agree with Gotte when he denies 

 that an Orthonectid possesses 'the possibility of becoming a 

 corpse' (in his sense of the word) because 'its death consists 

 in the dissolution of the structure of the organism.' When the 

 young of the Rhabdites form of Ascaris nigrovenosa bore 

 through the body-walls of their parent, cause it to disintegrate 

 and finally devour it, the whole organism disappears, and it 

 would be difficult to say whether a corpse exists in the popular 

 sense of the word. But, scientifically speaking, there is cer- 

 tainly a corpse ; the real soma of the animal dies, and this, 

 however subdivided, must be considered as a corpse. The 

 fact that natural death is so difficult to define without any 

 accurate conception of what is meant by a corpse, proves the 

 necessity for arriving at a scientific idea as to the meaning of 

 the latter. There is no death without a corpse — whether the 

 latter be small or large, whole or in pieces. 



If we compare the bodies of the higher Metazoa with those of 

 the lower, we see at once that not only has the structure of the 

 body increased in size and complexity as far as the soma is 

 concerned, but we also see that another factor has been intro- 

 duced, which exercises a most important influence in lengthen- 

 ing the duration of life. This is the replacement of cells by 

 multiplication. Somatic cells have acquired (at any rate in 

 most tissues) the power of multiplying, after the body is com- 

 pletely developed from the reproductive cells. The cells which 

 have undergone histological differentiation can increase by 

 fission, and thus supply the place of those which are being 

 continually destroyed in the course of metabolism. The differ- 

 ence between the higher and lower Metazoa in this respect lies 



