CHAPTER XII. 



EFFECTS OF REORGANIZATION AND THE ORIGIN OF 

 VARIATIONS IN THE PROTOZOA. 



In the preceding chapters we have developed the ideas that life 

 is organization; that vitality is the sum-total of actions, reactions 

 and interactions between and amongst the aggregate of substances 

 which make up protoplasm; that minute differences in the aggregate 

 of substances constitute differences in organization; that no two 

 organizations are identical; that with continued metabolism the 

 protoplasm of a given individual undergoes changes in organization 

 which are gradual but progressive; that such changes may be mani- 

 fested V)y structural differentiations and by physiological activities 

 which are characteristic of certain periods in the life cycle; and that 

 progressive differentiation leads to a condition of protoplasmic sta- 

 bility such that metabolic activities weaken or cease altogether. 



We have no desire to belittle or ignore the fact that observations 

 are not all in accord with the conclusions outlined above or to under- 

 estimate the significance of data which apparently do not agree 

 with them. We are attempting however, to formulate a conception 

 of organization and vitality which will embrace as large a field of 

 observational results as possible and to give a rational interpretation 

 of them. An important part of such an interpretation is concerned 

 with the effects of fertilization and parthenogenesis which are con- 

 sidered in the present chapter. 



1. EFFECTS OF REORGANIZATION ON VITALITY. 



If our fundamental thesis that continued metabolism leads to 

 functional weakening and ultimate cessation of vitality is correct 

 it follows that for continued life some reconstructive or reorganizing 

 operation is necessar.y. The phenomena attending cell division, 

 together with experimental evidence (see Chapter V) indicate that 

 such reorganization may occur with each division of the cell, and 

 that vitality of the protoplasm immediately after division is nor- 

 mally unhampered by accumulated products of activity in the form 

 of metaplastids or of substances which are beccmiing inert. The 

 deep-seated changes in organization which accom])any fertilization 

 and parthenogenesis have a similar but an even more profound effect 

 for the protoplasm is entirely made o\'er and new cell organs are 



