THEORIES OF INDIVIDUALITY 41 



tution. The process of individuation is the process of 

 establishment of the gradient or gradients as a more 

 or less persistent condition, and the degree of individua- 

 tion depends upon the permanency of the gradient, the 

 metabolic rate in the dominant region, the conductivity 

 of the protoplasm, and probably on other factors as well. 



From this point of view the assumption of a 

 mysterious, self-determined organization in the proto- 

 plasm, the cell or the cell mass as the basis of physio- 

 logical individuality becomes entirely unnecessary. The 

 origin of physiological individuality is to be found, not 

 in living protoplasm alone, but in the relations between 

 living protoplasm and the external world. In view of 

 the fact that the organic individual after its formation 

 is far from independent of its environment, it is difficult 

 to see why we should assume that it is independent and 

 self-determining in its origin. 



It must not be supposed, however, that every new 

 individual originates in the manner described above. 

 When the axial gradient is once established in a cell or 

 an organism, it may simply persist through the process 

 of cell division or other forms of reproduction so that 

 the unity and order of the new individual represent 

 simply the unity and order of the parent or a part of it. 

 In such cases the basis of individuality is inherited from 

 the parent. In nature we fi.nd both possibilities realized : 

 physiological individuality may arise de novo through 

 the relation between living protoplasm and its environ- 

 ment, or it may be inherited from previously existing 

 individuals. To put it more concretely, an axial gradient 

 cannot arise in the first instance independently of con- 

 ditions external to the mass of protoplasm concerned, 



