78 THE EVOLUTION OF DEATH 



in the year 1883 that we have become acquainted with the 

 history of the germ cells. Since these cells, properly speaking, 

 develop independently of the somatic cells, it becomes very 

 doubtful whether they can exert any such influence on the 

 body as Gotte's theory requires. Moreover, the fact that a 

 man may live, long in health after the reproductive capacity 

 is lost speaks against the theory. The theory of Hansemann^^ 

 may be considered to a certain extent as a modification of 

 Gotte's. Hansemann seeks the immediate cause of physio- 

 logical death in the atrophy of the germ plasm, but, as we 

 know, senescence is not a phenomenon which begins at the 

 end of life, but a continuous one which proceeds in yoimg 

 individuals also. It is therefore clear that we cannot explain 

 becoming old by an event which does not occur until the 

 individual is already old. 



The various hypotheses which we have just discussed have 

 this in common, that they seek to explain only the death of the 

 whole body, and do not investigate the question of death as a 

 phenomenon of cell Ufe. The theory of cytomorphosis differs 

 from the mentioned theory precisely therein that it regards 

 death as a phenomenon which occurs in single cells. It is, if 

 I am right, the only theory which we possess up to the present 

 time which answers to the demands of biology. 



As to the development of death we know little as yet. 

 NaturaUsts assume that unicellular organisms were developed 

 in the world earlier than the multicellular, or in other words, 

 that they are more primitive and older. We must therefore 

 assert that the first living cells were potentially immortal, as is 

 at present the case for their existing representatives. From 

 this it follows that natural death appeared later. It seems to 

 me probable that death as we now know it in the human race 

 was evolved gradually. In sponges and coelenterates we find 



