io THE PSYCHIC LIFE 



other observers, there exist also in vibratile cellules 

 filiform striae which seems to be a continuation of the 

 cilia, and which traverse the protoplasm of the cell 

 throughout its whole length. 



We might add to this direct observation several 

 other facts showing that the vibratile cilia are indeed 

 prolongations of the plasm. Under the action of 

 re-agents the cilia act like the cellular protoplasm; 

 they are coagulated by the acids and dissolved by 

 weak alkalies, while the cuticle offers a greater resis- 

 tance to these same agents. 



These vibratile appendices are not without analogy 

 with the pseudopodia of naked cells; Dujardin, a 

 French naturalist, demonstrated this in 1835, although 

 efforts have since been made to bestow the honor of 

 this discovery upon the Germans. Dujardin has 

 proved that the amoeboid movement and the ciliary 

 movement are only two manifestations of the con- 

 tractile power of protoplasm. In fact, if instead 

 of examining a pseudopod with lobed outline like that 

 of the amoeba, we observe the slender and filamentous 

 pseudopodia of the Foramenifera, we see that the ex- 

 tremity of the filament is agitated by the same vibra- 

 tory movement as the vibratile cilium. 



All the transitions from the fine and delicate cilia 

 to the large cilia, tapering in form like a stilleto, which 

 have been called cirri, have been observed; moreover 

 these cirri are formed of agglutinated cilia; by the aid 

 of certain re-agents they have been dissociated. 



An observation of a ciliated infusory, the Didinium 

 nasutum (see the illustration further on) made by M. 

 Balbiani, shows that the movement of the cirri is not 

 an involuntary movement like that of the cilia of the 

 vibratile epithelium, with which it has often been 



