CHAPTER II. 

 THE FUNDAMENTAL ORGANIZATION. 



Weismann's conception of a metazoon as made up of germinal 

 and somatic protoplasm is equally true of a protozoon. Here, 

 however, the two are combined in the make-up of a single cell, and 

 Weismann was not entirely right in considering all Protozoa as 

 equivalent to the germinal protoplasm only of Metazoa. In gen- 

 eral the derived organization of a protozoon is a combination of the 

 fundamental organization which retains its fundamental germinal 

 characteristics and the derivatives from it which characterize the 

 adult or fully differentiated individual. Like the metazoan somatic 

 plasm, these derivatives have a limited existence, and again like 

 somatic plasm, new ones are formed from the germinal protoplasm 

 with each successive act of reproduction. An essential difference 

 between the somatic structures of Protozoa and those of Metazoa, 

 is that such structures in Protozoa are reversible while in Metazoa 

 they are irreversible. It is important to make the attempt at least 

 to distinguish between the fundamental or germinal protoplasm 

 and the structures which are derived from it. The latter, as in 

 Metazoa, provide the structural features by which species are 

 differentiated and classified. 



Although with our present knowledge it is impossible to analyze 

 protoplasm and to discover the nature of the ultimate fundamental 

 organization which involves the differences between species, it is 

 possible by experiment and upon a morphological basis to determine 

 what protoplasmic parts are necessary for perfect development. 

 Thus, in the experiment with fragments of Stentor or Dileptus 

 (see p. 45), we find that no development occurs if nuclei are not 

 included in the fragments, and nuclei without cytoplasm are equally 

 impotent. So, too, in all encysted Protozoa, we invariably find 

 a combination of nuclei and cytoplasm. The legitimate inference 

 is that both nucleus and cytoplasm are necessary for continued 

 vitality and that interactions between these two primary components 

 are necessary for the formation of the structures of the derived 

 organization. This is such a fundamental biological truth that it 

 seems hardly necessary to emphasize it here. 



It is difficult to distinguish upon a morphological basis between 

 the visible differentiations of the fundamental organization and 

 structures of the cell which should be included more properly in 



