134 KIYOYASU MARUI 



NEUROFIBRIL STRUCTURE OF THE MAUTHNER CELL 



It is not the purpose of the present work to study the posi- 

 tion, general relations, and size of this wonderful cell. My main 

 purpose lies, on the contrary, in the further investigation of the 

 finest structure of this giant cell. I merely refer here to the 

 works of Mayser, Beccari (5), Herrick,^ Bartelmez (4), and 

 others in regard to those points. As far as the internal morphol- 

 ogy of the Mauthner cell is concerned, it would not do to ignore 

 the condition of the intracellular neurofibrils in the study of 

 synapse, since, as I mentioned above, the relation between extra- 

 and intracellular neurofibrils is not clearly decided yet. Though 

 Bartelmez and others described the neurofibril structure of this 

 cell, I will add the results of my study here, as there are many 

 points not sufficiently clear. 



The Cajal, Levaditi, and Bielschowsky preparations were 

 chiefly used in my study of the neurofibril structure of the 

 Mauthner cell. By means of the first two methods the neuro- 

 fibrils were exceedingly clear in many cases, but in other cases 

 they proved very uncertain in, their results. The cell was now 

 and then stained merely a diffuse yellow or brown, without any 

 neurofibrils being differentiated in it, and in other cases the 

 ground substance of the cell was also tinged more or less inten- 

 sive yellow or brown, so that the neurofibril structure did not 

 present itself clearly enough. In comparison with them, the 

 Bielschowsky technic offered always excellent results; I shall 

 therefore speak mainly of the Bielschowsky preparations, besides 

 giving consideration to the best preparations of Cajal and Le- 

 vaditi. Owing to the wealth of neurofibrils in the Mauthner 

 cell, the sections must be thin in order that the course of the in- 

 dividual neurofibril could be followed distinctly. 



The results of my investigation on the neurofibril structure in 

 Mauthner's cell harmonize in main features with those of Bethe 

 (6, 7), Bielschowsky (8, 9, 10), and Economo (15), in so far as 

 the neurofibrils do not form a real net-work in the cell. On the 



* Journal of Comparative Neurology, vol. 24, 1914, p. 343. 



