348 THE BIOC08MOS PARTICULARIZED. 



with its nomenclature (species, genera, 

 classes, families, tribes, etc.). (2) The past 

 forms of the animal world, as revealed in the 

 geologic ages, are to be set forth in their evo- 

 lution, which shows the existent fauna aris- 

 ing in time. (3) The present individual or- 

 ganism (say of man), in its genesis from its 

 earliest stage to its last, is seen re-evolving 

 the animal shapes of the past from their start, 

 recapitulating the historic rise of the whole 

 animal world in its own growth as individual. 



Now all three of these lines of development 

 have the common movement: they start far 

 back in the pre-cellular life-stuff, rise to the 

 uni-cellular status, and then conclude in some 

 form of cellular association. Such is their 

 unitary principle of evolution which indeed 

 underlies the million-fold grades and shapes 

 of animals and plants those now being, those 

 having been, and those getting to be. For 

 this reason the science of the cell (Cytology) 

 lies at the basis of Biology and unifies its 

 countless variety of forms. (See the preced- 

 ing exposition of Cytology, pp. 130-160.) 



Accordingly, if we wish to take a total sur- 

 vey of Animal-life as generated, we must go 

 back to the conception of the elemental life- 

 stuff (Protobioticon) both vegetal and animal, 

 to which we assign the primal differentiation 

 into Organic and Inorganic. In this pre-cel- 



