CILIATE FIBRILLAR SYSTEMS 259 



of the cell body, Parker suggested that neurofibrils generally, and possi- 

 bly the fibrils described for certain ciliates, may serve to transmit, from 

 the metabolic center or nucleus, metabolic influences "essential for the 

 continued life of the whole neurone." How these transmissions might 

 be made was not clear. He thought they might involve "chains of ionic 

 readjustment such as have been proposed as an explanation of the nerve 

 impulse." Aside from whether or not such might apply to the function 

 of the fibrils in ciliates, however, he rightly observed that these fibrils 

 may not be intimately associated with the nucleus, as seems to be the 

 case in neurones. 



Entz's (1893) interpretation of an elastic function for the Spasmonem 

 in the recoiling stalk of the vorticellids was discussed under the caption 

 "Interpretations." In addition to this, reference may be made briefly 

 to Koltzoff's (1903, 1906, 1912) similar interpretations for elastic 

 fibrils in cilia and in cells generally. He would ascribe elasticity to all 

 fibrils in maintaining all organic form other than spherical. Since proto- 

 plasm is liquid, as shown by the sphericity of its enclosed vacuoles, then 

 elastic elements must be postulated to counteract the physical forces of 

 inner and outer osmotic pressure and surface tension, which tend always 

 to efl^ect spherical form. Such elements are fibrillar, as observed in 

 the many kinds of cells investigated. The amount of evidence adduced 

 by Koltzoff is impressive, but his interpretation obviously cannot apply 

 exclusively to all fibrils. 



Similar claims for a supporting function for fibrils are rather wide- 

 spread in the literature. Thus Jacobson (1931), as already stated, is 

 disposed to attribute a supporting function to all noncontractile fibrils. 



These few citations, together with many others previously noted, may 

 serve to indicate the diversity of functions that have been variously 

 attributed to fibrillar differentiations in ciliates. In so far as they suggest 

 that these fibrils and fibrillar systems may differ in their structure, func- 

 tions, and relationships among the manifold kinds of ciliated Protista, 

 certainly no one could present conclusive evidence to the contrary. But 

 when, in the absence of proof, an investigator seriously contends that 

 in these unicellular organisms any and all fibrillar differentiations per- 

 form only one elementary function, whether it be that of elasticity, 

 mechanical support, contractility, conductivity, or "metabolic transmis- 

 sion," or when he assigns to these fibrils or fibrillar systems one or two 



