1 6 Journal of Comparative Neurology. 



resulting degeneration would enable me, by exclusion, to ascer- 

 tain the area of distribution of the neuraxes of the sympathetic 

 neurons removed in the respective ganglia extirpated. Tuckett 

 (8) has shown, — "that where non-medullated nerves degen- 

 erate, the core of the fibers of Remak, staining with methylen 

 blue, disappears, while the sheath and nuclei are unaffected by 

 cutting them off from their trophic nerve-cells. Degeneration 

 is shown, by the histological changes and physiological phenom- 

 ena, to begin about the twenty-fourth, while loss of irritability 

 and conductivity is complete by the fortieth hour." The 

 experiments on extirpation of the ganglia were all made on 

 cats. The operated animals were kept for a time varying from 

 3 to 49 days (see table) after extirpation of the ganglia. The 

 results obtained in this portion of my investigation are so 

 meager, that it does not appear to me advisable to give the 

 protocol of these experiments in detail ; I have therefore group- 

 ed the salient points in the table opposite. 



In summarizing the results given in this table, attention 

 may be drawn to the fact that in experiments where nerves in 

 the pial vessels were stained, after the extirpation of sympathetic 

 ganglia in the neck or thorax, the medullated nerve fibers accom- 

 panying the basilar or internal carotid and its branches were 

 stained. The extirpation of the ganglia, did in no way alter their 

 reaction to the methylen blue. This I take it may be put forth 

 as an additional argument, to those already given, that these 

 medullary nerve fibers are sensory. As to the distribution of 

 the vaso-motor fibers, the results are not conclusive. A study 

 of the table will show, that after extirpation of the superior cer- 

 vical ganglia the vaso-motor fibers on the anterior half of the 

 circle of Willis and the branches of the middle cerebral seem 

 less numerous or entirely wanting; the same is true of the basi- 

 lar artery and its branches after extirpating the inferior cervi- 

 cals or stellates or both. Yet after making comparisons between 

 the preparations obtained in these experiments and those obtain- 

 ed from normal animals, I am free to admit that the above con- 

 clusions do not seem justified. It should be stated that in 

 this research some sixty animals were used, and of this number 



