118 CAUDATE CELLS. 



caudate processes of a nerve cell may help to form a vast 

 number of dark bordered nerves, but it is, I think, certain that 

 no single process ever forms one entire axis cylinder" (187). 



" It is probable that the caudate nerve cells are not sources 

 of nerve force. These cells are fewer in number, and com- 

 paratively insignificant in the lower vertebrata, particularly 

 batrachia and fishes. In the invertebrata they do not exist at 

 all, and it is doubtful if any ' cells ' precisely corresponding to 

 them are to be found in their stead. The bioplasm of the nerve 

 cell is embedded in the material which exhibits the lines cross- 

 ing in all directions, and no doubt this substance is formed 

 from it ; but as far as I have been able to ascertain, no nerve 

 fibre arises from, or is connected with, the bioplast (nucleus, or 

 nucleolus). It appears probable that the caudate cells are the 

 stations at which nerve fibres pursuing many different directions 

 decussate and change their course" ("Biopl.,"p. 190). 



We have thus a central counterpart of the commissural 

 peripheral plexus formation, and it is interesting to note that 

 Professor Bain, looking at the subject from a totally different 

 side, arrived at conclusions concerning the arrangement of the 

 central nervous mechanism agreeing in all important particulars 

 with those of Dr. Beale. 



" From the foregoing observations the reader will be led to 

 conclude that I regard a nervous apparatus as consisting essen- 

 tially of fine fibres and masses of bioplasm, which form unin- 

 terrupted circuits. The fibres are continuous with the bioplasts, 

 of which some are central, some peripheral, and grow from 

 them. Currents emanating from bioplasts at one part of the 

 circuit would influence the changes in the bioplasts in another 

 part, and the last react upon the first " (" Biopl.," p. 209). 



Such is a brief view of the anatomical elements of 

 the nervous system according to Dr. Beale. The most 

 important additions made by him to our knowledge 

 are, the extreme number and minuteness of the fine 

 fibres, and the compound nature of even these ; the 

 commissural nature of the caudate cells, and the peri- 



