454 Journal of Applied Microscopy. 



.019 to .023 mm. in the normal fiber; there are wavy, undulating lines, instead 

 of the longitudinal striae, and the individual fibrillae become twisted upon each 

 other like the strands of a rope. This occurs after the marginal deposit, which 

 culminates in the vesicular formation surrounding the nuclei. In the final stage 

 of degeneration there is a cylindrical plug of large vesicles containing the dis- 

 torted nuclei and particles of pigment, through which a shadowy longitudinal 

 line shows the position of the former fibril. Over one hundred slides were 

 examined without finding any trace of regeneration. 



The material was fixed in Zenker's fluid, five per cent, formalin, and mercuric 

 bichloride. Celloidin was used for imbedding, and sections were stained in 

 Delafield's haematoxylin, Weigert's fibrin stain, VanGieson's picric acid-fuchsin, 

 Ehrlich's triple stain, and a one per cent, aqueous solution of thionen. Glycerine- 

 Heidenhain-haematoxylin was also used. Sections are stained in this from twelve 

 to twenty-four hours, and do not need to be decolorized. E. M. Brace. 



NEUROLOGICAL LITERATURE. 



Edith M. Brace. 



Literature for Review should be sent to Edith M. Brace, Biological Laboratory, 

 University of Rochester, Rochester, N. Y. 



Huber, G. Carl. Observations on the Innerva- The results of the experiments oppose 

 tion of the Intracranial Vessels. Jour. (.^g ^ig^^g ^f physiologists as sunimar- 

 Comp. Neur. 9: 1-25, i pi., 1899. ^ ^ *= 



ized by Hill, who says : " No evidence 



has been found of the existence of cerebral vaso-motor nerves." 



Experiments were made upon dogs, cats, and rabbits. There are both 

 meduUated fibers (sensory) and non-medullated fibers (vaso-motor) in the 

 pia mater. The bundles of medullated fibers wind around the arterial vessels 

 in long sweeps, dividing where these vessels divide, and exchanging fibers 

 so that a wide-meshed network is formed. The fibers branch off at the nodes 

 of Ranvier, and the division into smaller and smaller medullated fibers 

 continues until the branches terminate in fine varicose non-medullated fibrils, 

 which usually end in a small granule. Non-medullated fibrils also proceed from 

 the medullated fibers at the nodes of Ranvier. Many of these terminal branches 

 are thought to terminate in the adventitia of the vessels, or in the fibrous tissue 

 surrounding them. No medullated fibers were found accompanying the veins of 

 the pia. 



There is also a perivascular plexus of non-medullated (vaso-motor) fibers 

 which was found from the larger vessels, constituting the circle of Willis, to 

 vessels with a muscular coat of not more than two layers of involuntary muscle 

 cells. These resemble the vaso-motor nerves found in the wall of vessels in 

 other parts of the body. Within this perivascular plexus there is a second plexus, 

 not as well defined, which seems to lie just outside of the muscular coat. The 

 termination of the ultimate fibrils of the plexuses may be seen in the muscular 

 coat of the pial vessels. These fibrils run parallel to the long axis of the involun- 



