Roth, Spinal Accessory Nei've. 487 



(1892) indeed, obtaining no response to stimulation of roots 

 above the first thoracic. And furtliermore the latter author 

 found no evidence of the existence of vaso-constrictor fibers for 

 the head, of secretory fibers for the submaxillary gland or of 

 accelerator fibers for the heart in the anterior roots of nerves 

 above the first thoracic. 



It is to be noted, however, that these results were obtained 

 by stimulation of the anterior roots of the spinal nerves. At 

 an earlier date Francois-Franck (1878), working in Marey's 

 laboratory obtained quite different results by the direct stimula- 

 tion of the rami communicantes. He isolated in the cat the 

 lower cervical and upper thoracic rami, and after severing their 

 connections with the roots of the spinal nerves stimulated each 

 one independently, with the result that he obtained dilatation 

 of the pupil on stimulation of the rami of all the nerves from 

 the sixth thoracic to the fifth cervical inclusive, and he conclud- 

 ed that "la moelle cervico-dorsale, entre le niveau de la 5'"*^ 

 cervicale et de la 6"'^ dorsale, fournit au ganglion i'^' thoracique 

 des rameaux convergentes qui contiennent tous, en plus ou 

 moins abondance, de filets irido-dilatateurs." 



These results are clearly much more in harmony with the 

 anatomical observations recorded above, and it becomes an 

 interesting question to determine the cause of the discrepancy 

 between the results which followed stimulation of the anterior 

 roots and those following stimulation of the white rami. This 

 question did not, however, fall within the scope of the present 

 study as it was originally planned, and I shall now proceed to 

 consider the relations which exist between the roots of the 

 spinal accessory nerve and the occurrence of white rami fibers 

 in the rat. 



Observations ojt Rats. 



In five rats the spinal cord was exposed by carefully cut- 

 ting away the neural arches of the vertebrae, and the spinal 

 accessory was then traced down the cord with the aid of a dis- 

 secting microscope. In each animal the lowest roots on both 

 sides emerged from the cord just above the roots of the fourth 



