The Journal of 



Comparative Neurology and Psychology 



Volume XVI NOVEMBER, 1906 Number 6 



THE MODE OF CONNECTION OF THE MEDULLATED 

 NERVE FIBER WITH ITS CELL BODY 



BY 



OLIVER S. STRONG. 

 (^Columbia University.') 



With Plate XIX. 



One of the principal lacunae in our present knowledge of the finer 

 structure of the nervous system concerns the relations between the 

 medullated and non-medullated portions of the nerve fibers — our 

 ignorance of precisely what parts are medullated and what are not. 

 This has been brought out by NissL in his book on the Neurone 

 Theory, and, while Nissl is doubtless overexacting in his require- 

 ments as to what is necessary to practically establish neuro-histo- 

 logical relations, yet he has done a service in calling attention to 

 the somewhat surprising lack of actual observation of certain rela- 

 tions which have been taken more or less for granted. The princi- 

 pal terra incognita is, naturally, that portion of the distal end of the 

 nerve fiber extending from where the sheath ends to the pericel- 

 lular termination. There is also some deficiency in our actual 

 observation regarding the proximal end of the fiber, especially its 

 acquisition of the sheath. Nissl has also called attention to this 

 fact. 



The reasons for these deficiencies lie naturally in the defects of 

 our histological technique. We have precise methods for demon- 

 strating the sheath and also methods for displaying the naked axis 

 cylinder process, but still lack a practical specific axis cylinder 

 stain. We also lack a good method for combining these two 

 pictures and demonstrating at once the medullated and non- 

 medullated parts of the nerve fiber. 



The present note does not profess to furnish such a method, nor 

 to fill in the most important of the gaps above mentioned, but 



