Organisms Consisting of One Cell 245 



system and the micronucleus does not fall in very well with 

 accepted views touching the general character of these two 

 kinds of substance in the metazoa. But the general anatomy 

 of the system, and its relation to other organs undoubtedly 

 favor the belief that it is nervous. "All parts," says Sharp, 

 "connected with the neuromotor system act in perfect co- 

 ordination." And it should be said that this assertion 

 was based on attentive study of the living animals. "In 

 watching these phenomena of retraction and expansion in 

 the living, active animals one cannot help but be impressed 

 with the wonderful co-ordination of parts." 



The idea that neural elements occur in the protozoa is, 

 as is well known, not new. The most definite report to this 

 effect previously made, is that by Neresheimer. This au- 

 thor describes fibers in S tent or running parallel with and in 

 general accompanying the mvonemes. He believes these to 

 be nervous and calls them neurophanes. The observation 

 has not been confirmed so far as I am aware; and one ob- 

 server, O. Schroder, believes that Neresheimer is in error 

 as to the existence of any such fibers in these animals. Nere- 

 slteimer's, and particularly Sharp's, reports will undoubted- 



tc-all forth renewed studies in this important field. 

 ! 

 - 

 I 



A More Critical Examination of the Term "Organ" 



The parts of the protozoa occupied with determining the 

 nature's place in space arc perhaps those to which the ap- 

 lication of the term organ is avoided with greatest diffi- 

 ilty. "In the majority of Protozoa," says Calkins, "move- 

 ment is accomplished by the activity of special motor or- 

 gans, which may be either changeable processes (pseudopo- 

 dia) or permanent vibratile appendages (flagella and cil- 

 ia)." - l This is a favorable place to remark on the justifia- 

 bility of calling pseudopodia (and other transitory cell 

 parts for that matter) organs. Science demands consist- 



