490 Journal of Comparative Neurology and Psychology. 



hardened in osmic acid and sections cut, they are seen to have 

 the characters of white rami ; that is, they consist chiefly of 

 small meduUated fibers collected in bundles, with a few medium 

 or medium sized fibers ; between the bundles are a variable 

 number of noii-meduUated fibers; besides these there .one or 

 more grey rami, z'.i?. , bundles consisting chiefly of non-medul- 

 lated fibers, but containing scattered medullated fibers." 



These results are entirely in harmony with the author's 

 experimental observations and show a marked discrepancy be- 

 tween the occurrence of efferent white rami fibers and the 

 development of the spinal accessory. 



In four out of five cats examined in connection with the 

 present study, the level of the lowest root of the spinal acces- 

 sory agreed with that assigned to it by Bischoff, that is to say, 

 it occurred at the level of the sixth cervical nerve. In the fifth 

 individual, however, the nerve of the left side extended down 

 the cord only to the level of the fifth cervical nerve, that on the 

 right side agreeing with the findings in the other individuals. 



In two of the four individuals in which the development of 

 the spinal accessory was symmetrical in the two sides, it was 

 found that the ramus communicans given off from the sixth 

 cervical nerve contained a very few scattered medullated fibers. 

 That from the seventh nerve however, contained a large num- 

 ber of white rami fibers. In the fifth animal, in which the 

 development of the spinal accessory was unsymmetrical, sec- 

 tions were made of the anterior roots of the spinal nerves after 

 treattnent with osmic acid, but unfortunately the rami were not 

 studied, and as regards the anterior roots, it was not found pos- 

 sible to make a count of the smallest fibers, which could be 

 regarded as sufficiently accurate for record. It was certain, 

 however that a m irked increase in the number of these fibers 

 occurred in a definite anterior root on each side and this increase 

 was correlated with the level of the lowest root of the spinal 

 accessory. Thus it was found that on the left side, on which 

 the spinal accessory descended to the level of the fifth nerve, 

 the sudden increase of small fibers occurred in the anterior root 

 of the sixth nerve, while on the right side, in which the access- 



