80 ANIMAL INDIVIDUALITY [OH. 



hydroid colony, and so, even were the detached 

 larval part to regenerate a new stomach and become 

 a separate self-supporting organism (as is not un- 

 thinkable) we should not be able to draw any 

 conclusions applicable to colonies produced by 

 ordinary fission or budding. 



There is another reality on which, unconsciously, 

 the theory is based. In all Metazoa there is, before 

 and during the sexual process, a shuffling and recom- 

 bination of the chromosomes of the nucleus those 

 bodies which taken together appear to determine the 

 characteristics of the offspring, or at least those which 

 mark it off from others of the same species, whether 

 it shall be tall or short, fair or dark, chubby or lanky, 

 tip-tilted or Roman-nosed. More, it was supposed 

 that this rearrangement only took place during 

 sexual fusion, and instances were adduced of many 

 vegetable "sports," or mutations as they are now 

 often called, so many of which have been enumerated 

 by De Vries. A plant will often appear showing a 

 mutation in all its parts, so that the change inducing 

 the mutation must certainly have affected the single 

 sexually-produced cell from which the whole plant 

 has sprung. Once formed, mutations will persist in 

 cuttings or slips of the parent plant, but will usually 

 be lost when the sexual chromosome-shuffling is 

 allowed to take place and offspring are raised from 

 seed. In such cases then, all the plants that have 



