NON-MEDULLATED NERVE FIBERS IN THE SPINAL 



NERVES 



S. WALTER RANSON 



From the Anatomical Laboratory of the Northwestern University Medical School 



SEVEN FIGURES 



It is generally admitted that in the cerebro-spinal nerves 

 there are a few non-medullated fibers, supposedly derived from 

 the sympathetic system : but a study of the spinal nerves by va- 

 rious silver-impregnation methods has led me to believe that the 

 non-medullated fibers are very numerous, even exceeding in 

 number those which are medullated. A preliminary note on 

 this subject was published in May, 1909, and some of the prepara- 

 tions were demonstrated at the meeting of the American Associ- 

 ation of Anatomists (December 28, 1909). Similar observations 

 have been made on the nervus intermedins by Weigner ('05). 



MATERIAL AND METHODS 



Observations have been made upon the spinal nerves of men, 

 dogs, cats, rabbits and rats. In animals the sciatic and the 

 lower cervical and lumbar nerves including their roots and dorsal 

 root ganglia were examined. Two human sciatic nerves which 

 had been obtained fresh from amputated limbs were also studied. 

 For these I am indebted to Dr. G. D. Scott and Dr. Wm. Speidell. 



For the demonstration of the myelin sheaths the Pal-Weigert 

 method and the method of Stroebe were used. These are so 

 well known that no account of the technique need be given. It 

 should be said, however, that in the differentiation of the Pal- 

 Weigert preparations great care was exercised not to decolorize 



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