42 SCIENCE PROGRESS. 



fibres which run directly into the sciatic. The constrictor 

 fibres are situated in the lower thoracic and upper lumbar 

 and pass through the sympathetic chain. The presence of 

 these fibres in the posterior roots has given rise to much 

 discussion. Strieker's results were confirmed by Gartner, 

 but denied by Vulpian, Cossy, etc. Of recent workers 

 Morat^ cannot confirm the presence of these fibres, but on 

 the other hand Hasterlik and Biedl - confirm Strieker's 

 experiments. In this connection we find anatomical 

 evidence of the presence of fibres in the posterior roots 

 which have the characters which are usually reoarded as 

 typical of efferent fibres. Ramon-y-CayaP describes fibres 

 passing through the posterior roots and without branching 

 going straight to the anterior horn, where they end in nerve- 

 cells. V, Lenhossek * also describes similar fibres and 

 cells — the fibres passing though the posterior root ganglion 

 without becomino: connected with cells in that oanoHon. 

 Lastly V. Gehuchten ^ finds similar cells in his examination 

 of the spinal cord of the fowl at early stages of development. 



Werziloff ^ has recently published further experiments in 

 this direction. He employed for his experiments large dogs 

 which were curarised and under chloroform. His methods 

 were two in number ; either to examine temperature 

 changes as each posterior root was cut, or to place the 

 hinder leg in a plethysmograph and so obtain tracings of 

 the changes in volume. He describes very positive evi- 

 dence of vaso-dilator fibres in the sixth and seventh lumbar, 

 and first sacral posterior roots for the foot and similar fibres, 

 though less numerous, in the fourth and fifth lumbar for 

 the upper part of the leg and lower part of the thigh. 



Gaskell "* especially examined the posterior roots of the 

 first, second and third sacral for the presence of vaso-dilator 



^ ArcA. de Physiol., vol. xxiv., p. 689, 1892. 



2 Wiener, klin. Wochenschr., p. 43, 1893. 



^ Anat. Anz., vol. v., p. 112, 1890. 



* Ibid., p. 360, 1890. 



'" Ibid., vol. viii., p. 215, 1893. 



^ Centr. f. Physiol., vol. x., p. 194, 1896. 



~ Journ. of Physiol., vol. viii., 1887 ; Proc. Physiol. Soc, p. 4. 



