REPRODUCTION AND GROWTH 171 



in man. {ii) There is sinister or " eml " growth and this is 

 best manifested in conditions such as we see in cancers, in 

 bacterial cultures, in the riotous disorderly growth of a tropical 

 jungle, or in a seething mass of maggots, infesting some organic 

 substance. 



In such conditions growth has, to us, some strongly repellent 

 aspect and in searching for the roots of this feeling we find them 

 in a kind of intolerance, a destructive tendency, a want of order 

 of some kind. Life here expresses itself merely as the insistent 

 effort to make inorganic matter alive. It is, in some way, life 

 that is more elementary than the life of the higher organism — it 

 is life that may have been more characteristic of a former phase 

 of the passage of nature than life is, as we know it, at the present 

 time. 



62. ON THE MEANS OF GROWTH : CELL-DIVISION 

 Growth in the organic body may be a simple process of accre- 

 tion. Thus bone in an animal may consist largely of calcareous 

 material deposited round itself by a living bone-cell, and so with 

 many other growth-processes both in plants and animals. But 

 organic growth in all the multicellular organisms involves the 

 process of cell-multiplication. The bodies of all higher organisms 

 are structures formed by cells and these units have certain limiting 

 sizes which are always very small relatively to the size of the 

 organism. Whatever the nature of the latter, the order of size 

 of the component cells is much about the same. Therefore the 

 mass of the body of an organism is, in general, proportional to 

 the number of the constituent cell-units and in growing the 

 numbers of cells increase. 



62a. Cell-division. 



i. The gross aspects. The cell displays a constriction so that 

 it comes to have the appearance of an hour-glass. The constric- 

 tion becomes fine and then breaks so that one " parent-cell " 

 becomes two " daughter-cells." Each of the latter has at first 

 one-half of the mass of the " parent-cell," but it grows (by 

 assembling materials absorbed from the nutritive medium) and, 

 as it grows, its structure differentiates again so that it becomes 

 similar to the *' parent-cell." Each " daughter-cell " again re- 

 divides, grows and differentiates in the same way until the number 



