84 BIOLOGICAL LECTURES. 



be admitted that their real significance can only be under- 

 stood when each is taken in connection with the others, 

 the tout ensemble of which form the life of the nucleated 

 cell. If any explanation of special phenomena be attempted, 

 it should be in the light of what we know of the whole. 



We do not gain much, however, by so saying, as long as 

 this knowledge of the whole is merely a name for the sum 

 total of incoherent observations on diverse cell-phenomena. 

 Beneath and beyond all vital manifestations of a cell, there 

 must exist a primary physiological condition, on which the 

 details of secondary cell-phenomena depend. Just what con- 

 stitutes the primary physiological phenomenon of the cell, 

 is the point that I wish to discuss in the present paper, 

 believing, as I do, that such a problem as that of cell-organ- 

 ization, can be approached from the functional side with 

 better effect than has thus far been attained from the side of 

 pure morphology. 



Before we proceed further, it may not be out of place here 

 to introduce a general schematic description of a nucleated 



cell.i 



Excluding the centrosome and chromatophore for the present, 

 an animal cell may be described as composed of two sharply 

 distinct organs : the cell-body {eytosonie), and the nucleus 

 {caryosonie). 



The nucleus, in its "resting stage," has a definite membrane 

 around it, called the nuclear membrane or caryotlieea. The 

 cell-body consists of a net-work of cytoplasm. This net-work 

 contains within its own substance small bodies of varying 

 sizes, which are known as the microsomes or, more strictly, 

 the cytomicrosomes. Surrounding the cytosome, there is a 

 membrane known as the cell-membrane or cytotJteea. It may 

 exist as a thickened border of the cytosome or as a distinct 

 membrane separated from the cytosome. 



1 The descriptive cytological terms adopted here have merely an anatomical 

 significance, and do not refer to the chemical or functional properties of the struc- 

 ture. Several terms recently used by Hscckel (Aiit/iropos^oiif, 4th edition, Leipzig, 

 1891), have therefore been found most convenient. ( )nly the more salient features 

 of the cell will be emphasized in this place, that being sufficient for our present 

 purpose. 



