2 INDIVIDUALITY IN ORGANISMS 



living forms, and many individuals are made up of 

 other individuals and these in turn of others. Divisi- 

 bihty is as characteristic of the organic individual as 

 indivisibihty. Nevertheless individuahty is a very real 

 thing in the organic world. There may often be diffi- 

 culty in determining the presence or absence of indi- 

 viduality or the limits in space or time of particular 

 individuals, but such difficulties do not in the least 

 shake our faith in the existence of the individual. What- 

 ever the anatomist and the histologist tell us concerning 

 the constitution of the human body, of hundreds of 

 organs and millions of cells, it is perfectly evident that 

 each human being is an individual, because his behavior 

 proves it. And the same is true for the single cell with 

 its nucleus, cytoplasm, centrosomes, plastids of various 

 kinds, '^ mitochondria," chromosomes, chromomeres, etc. 

 We call the cell an individual because of its behavior. 



What then are the fundamental characteristics of 

 this behavior ? In what does the individuality consist ? 

 In the first place, the organic individual is alive and 

 therefore consists essentially of the complex of substances 

 termed in general protoplasm; secondly, it is more or 

 less definitely limited in size; thirdly, it possesses a 

 more or less definite morphology, a visible form and 

 structure, which is associated in some way with dynamic 

 and primarily chemical activity; fourthly, a greater or 

 less degree of order, co-ordination, correlation, or har- 

 mony, as it is variously called, is perceptible in the char- 

 acter of its form and structure and in the dynamic 

 activities of its constituent parts. In short, the organic 

 individual appears to be a unity of some sort, its indi- 

 viduahty consists primarily in this unity, and the process 



