CILIATE FIBRILLAR SYSTEMS 225 



he had described for Paramecium and Frontonia, might function in the 

 well known metachronism of ciliary movement. He was not inclined, 

 however, to compare these fibrils with Neresheimer's neurophanes nor 

 with the neurofibrils of the Metazoa. Obviously, since it had not yet 

 been proved that the neurofibrils were the conductive elements of nerves, 

 then an analogy between these neurofibrils and the fibrils found in 

 Paramecium would not add to our understanding of either the one or 

 the other. 



Mention may here be made of the system of fibrils described for 

 Paramecium by Rees (1922). These have an arrangement and relation- 

 ship quite different from any of the fibrils referred to above. According 

 to Rees, all of the fibrils he observed connected the basal granules of 

 the cilia of the body and cytopharynx with the motorium, located just 

 anterior to the cytostome, by coursing through the cytoplasm in several 

 graceful whorls. 



From the results of his few experiments, Rees concluded that these 

 fibrils were conductive in function. By severing with a microneedle the 

 fibrils connecting the cytopharyngeal membranelles with the motorium, 

 the coordinated movements of these membranelles was interrupted. Like- 

 wise, the coordinated movement of body cilia was interrupted when the 

 neuromotor center was destroyed. 



In view of the later descriptions of the more peripheral system of 

 fibrils in Paramecium, Rees's experiments should be repeated. It may be 

 noted also that Jacobson (1931) reinvestigated this fibrillar complex 

 described by Rees, and concluded that he had observed not fibrils but 

 internally discharged trichocysts, as effected by the killing agents used. 

 Her figures of fixed Paramecium illustrating such trichocysts are com- 

 parable to some of Rees's figures, except for certain regularities in the 

 "fibrillar whorls" depicted by Rees. One could suppose that the in- 

 ternally discharging trichocysts might tend to follow the course of these 

 whorls of fibrils and so reproduce that course in fixed material, which, 

 through differential staining, revealed the trichocysts but not the fibrils. 

 Only further careful investigation can clarify this discrepancy. 



The interpretations of von Gelei (1925-31) and of Klein (1926-32) 

 agree in ascribing a conductive function to the inner fibrillar complex 

 of Paramecium, but their views on the relations and functions of its 

 outer fibrillar complex are not in accord. The basis for their interpreta- 



