374 THE BIOLOGY OF STENTOR 



orderly transformations. Stentor has such an architecture or 

 cortical pattern which is even visible in its heterogeneity in the 

 living organism and therefore can be rearranged at will. In dividing 

 stentors the migrations of the carbohydrate reserves mimics the 

 segregation of distinctive ooplasms in certain eggs, while in the 

 ^gg coat which Holtfreter (1949) has shown to be so important in 

 embryogenesis we may have a direct descendant of the ciliate 

 pellicle. We are reminded, too, that Hthium has marked morpho- 

 genetic effects on stentors as it does on embryos. Truly, we do not 

 know which of these resemblances are superficial and which are 

 fundamental, but no possible correspondencies should be ignored. 



5. Theoretical considerations 



Before the nucleus was discovered and even after this cell 

 organelle was found to be present but not obviously active except 

 in reproducing itself at cell division, the emphasis w^as on the 

 cytoplasm as the basis of life. All cytoplasms were said to have a 

 common denominator in *' protoplasm", a semifluid substance 

 conceived as *' living matter". Of this view there remains today 

 only the fact that living organisms are intimately involved with the 

 colloidal state, and the hope that all living phenomena will be 

 explainable in terms of molecules and their interactions. With the 

 discovery of the nucleus and its importance in inheritance the 

 emphasis shifted in the other direction, and the nucleus was 

 regarded as ''the heart of the cell", or, currently, as ''containing 

 all the information for the organism". Yet both cytoplasm and 

 nucleus are necessary as a natural and inescapable dualism pre- 

 sented by the cell. Of course these two parts of the cell interact, 

 and Verworn (1892) early conceived a scheme embracing possible 

 interactions, excepting the more sophisticated modern concept of 

 steady states. Simply stated, we want to know what the nucleus 

 does and how it does it, what the cytoplasm does and how this is 

 accomplished, as well as how the two phases cooperate in the life 

 of the cell. 



The nucleus seems to serve as a chemical factory for the cyto- 

 plasm, producing essential substances or the means of their pro- 

 duction, apparently coenzymes. Apart from itself growing and 

 replicating, the nucleus contributes substances into the cytoplasm 

 where reactions leading to metabolism and structural growth take 



