196 INDIVIDUALITY IN ORGANISMS 



other parts in the animal, belongs in the same category 

 with the reproductive processes which give rise to new 

 whole organisms. In such cases physiological isolation 

 may be partial or with reference to a specialized con- 

 stituent individual of the organism. 



The localization of reproduction in the individual 

 may be determined by various other factors besides 

 distance from the dominant region. Some parts less 

 distant than others may be physiologically isolated 

 earher because of lower conductivity of paths, or because 

 of other correlative conditions within the organism, or 

 because of certain external conditions. In isolated 

 parts the least differentiated cells or regions, or those 

 with the highest metabolic rate, are likely to react earlier 

 than others and so determine the localization of the 

 reproductive process. Sometimes, particularly among 

 plants, in reproductions which occur with advancing 

 age or under depressing conditions, it is the original 

 dominant region which separates from other parts as 

 a smaller individual and so becomes the reproductive 

 body, spore, or whatever it may be called. 



Special unrecognized factors may play a part in 

 certain cases, but it seems impossible to doubt that, in 

 general, agamic reproduction in organisms results from 

 physiological isolation of parts of the individual. Indi- 

 viduation is a physiological integration depending pri- 

 marily on the dominance and subordination of parts in 

 relation to an axial gradient or gradients, and agamic 

 reproduction is a physiological disintegration of this 

 unity which makes possible new integrations. 



The fundamental similarity in individuation and 

 reproduction in the lower animals and plants is well 



