468 



BIOLOGY OF THE PROTOZOA 



or to nullify any one link in the chain of vital activities will have its 

 effect on the o:eneral vitality. 



It is not improbable that internal reorganization, or disorganiza- 

 tion, with increase or decrease of activity in all or in some part of 

 the proto])lasmic make-up may bring about similar variations in 

 vitality. Thus changes in organization may be effected by amphi- 

 mixis or ])y long-continued metabolic functioning with correspond- 





Fiu. 19G. — Urolcptus mohilis. Division of double individual; t.\pe with one divis- 

 ion nucleus. D, the single nucleus formed by fusion of the two independent sets of 

 macronuclei; E, first division of the single nucleus; F, reconstruction after division 

 with a new type of macronucleus formed from the single division nucleus. (After 

 C'alkins.) 



ing effects upon the general \'itality. The chemical and physical 

 make-up of the protoplasm of an individual may change with con- 

 tinued metabolic activities and lead to a change from what is termed 

 a labile condition when actions, reactions, and interactions are per- 

 fectly balanced and at a maximum of activity, to a more stabile 

 condition when these activities become increasingly luibalanced or 

 cease alto<»;ether. 



