DEATH 275 



the reproductive cells with the perpetuation of the 

 species. 



The normal life-cycle of a Metazoon is as follows : 

 The fertilised egg, or reproductive cell, by repeated 

 division gives rise to a number of cells, of which 

 some become the somatic cells i.e., the body of the 

 individual animal while others remain as its repro- 

 ductive cells ; from these latter, in due course and 

 in similar manner, the individuals of the next 

 generation are formed. Of the two kinds of cells, 

 the somatic cells alone are liable to natural death : 

 the reproductive cells survive as the individuals of 

 the succeeding generation. The reproductive cells 

 of Metazoa are therefore immortal, in exactly the 

 same sense as are Amoebae. The reproductive 

 cells, like the Amoebae, can be destroyed, but they 

 do not die naturally. Each reproductive cell is 

 derived by fission from a corresponding cell of the 

 preceding generation ; and in Metazoa, as in 

 Protozoa, there has been from generation to genera- 

 tion direct continuity of living matter. We are 

 apt to think of the somatic cells i.e., the body of 

 the individual animal as the essential part, by 

 reason of its greater bulk and impressiveness ; and 

 to regard the reproductive cells as structures whose 

 purpose it is to give rise to the somatic cells i.e., 

 the individuals of the next generation. In doing 

 so however we lose sight of the true relation 

 between the two groups of cells. The reproductive 

 cells are the really essential elements, and the part 

 of the somatic cells is a subordinate one ; their 

 purpose being to nourish and protect the repro- 



