192 CILIATE FIBRILLAR SYSTEMS 



But similar difficulties in comparing microscopic with macroscopic 

 forms of life had confronted investigators several years before von Sie- 

 bold's pronouncement and, in fact, before the concept of cellularity had 

 been definitely formulated. As is well known, this all culminated in 

 the Ehrenberg-Dujardin controversy, beginning in 1835- Obviously for 

 these investigations, the issue was not one of cellularity, but it had to 

 do with complexity versus simplicity in the organization of the Infusoria. 

 It seems probable that Ehrenberg defended his thesis of "complete or- 

 ganisms" partly in refutation of the theory of spontaneous generation, 

 then vigorously championed for microorganisms. At any rate, he sought 

 to identify in the Infusoria all the organs common to other animals. 

 Much of his adduced evidence, it will be recalled, was successfully re- 

 futed by Dujardin, who described among other things, his newly dis- 

 covered "sarcode" in support of his contentions for uniqueness and sim- 

 plicity in the organization of the Infusoria. 



The essentials of these contrasting views of Ehrenberg and Dujardin 

 on the nature of infusorian organization have recurred, in varied guise, 

 many times in the literature since their day. These opposing viewpoints 

 have, of course, become translated into terms of the concept of cellu- 

 larity, so that now the nature of unicellular organization, or "proto- 

 plasmic differentiation," is commonly contrasted with "cellular differ- 

 entiation" of multicellular organisms. 



Accordingly, in the following review of literature on fibrillar systems 

 in ciliates, it will become evident that some discrepancies in both the 

 analysis of structure and the interpretation of functions may owe their 

 origin largely to contrasting points of view on the essential nature of 

 "protoplasmic differentiation" in the Protozoa and "cellular differentia- 

 tion" in the Metazoa. 



Before beginning that review, however, the fact should be emphasized 

 that, as Maupas (1883) has pointed out, the Ehrenberg-Dujardin con-, 

 troversy marks a turning point in protistological investigations. Not only 

 did it enlist a wider interest in these microorganisms, but it made clear 

 the necessity of a critical structural analysis of their greatly diversified 

 types of organization and of a comparative study of such types before 

 any satisfactory interpretations were possible. 



The literature resulting from those analyses is so voluminous that 

 when one undertakes to review the accounts of a given system of organ- 



