Il8 THE STORY OF THE LIVING MACHINE. 



into such prominence as to hide from view the 

 more familiar protoplasm. The marvellous activi- 

 ties of the nucleus soon caused it to be regarded 

 as the important part of the cell, while all the rest 

 was secondary. The cell was now thought of as 

 a bit of nuclear matter surrounded by secondary 

 parts. The marvellous activities of the nucleus, 

 and above all, the fact that the nucleus alone 

 is handed down from one generation to the next 

 in reproduction, all attested to its great impor- 

 tance and to the secondary importance of the rest 

 of the cell. 



This was the most extreme position of the cell 

 doctrine. The cell was the unit of living action, 

 and the higher animal or plant simply a colony of 

 such units. An animal was simply an association 

 together for mutual advantage of independent 

 units, just as a city is an association of indepen- 

 dent individuals. The organization of the animals 

 was simply the result of the combination of many 

 independent units. There was no activity of the 

 organism as a whole, but only of its independent 

 parts. Cell life was superior to organized life. 

 Just as, in a city, the city government is a name 

 given to the combined action of the individuals, 

 so are the actions of organisms simply the com- 

 bined action of their individual cells. 



Against such an extreme position there has 

 been in recent years a decided reaction, and to- 

 day it is becoming more and more evident that 

 such a position cannot be maintained. In the 

 first place, it is becoming evident that the cell 

 substance is not to be entirely obliterated by the 

 importance of the nucleus. That the nucleus is 

 a most important vital centre is clear enough, but 

 it is equally clear that nucleus and cell substance 



