332 



Prof. W. M. Hicks. 



peripheral end of the cervical sympathetic, and formed nerve- 

 endings around the cells of the superior cervical ganglion, or they 

 had united directly with the sympathetic fibres. That the former 

 had taken place I infer from the fact that the regenerated nerve 

 contained medullated fibres larger than those proper to the sympa- 

 thetic. 



T conclude from the experiments that there is no essential differ- 

 ence between the efferent "visceral" or "involuntary" nerve fibres, 

 whether they leave the central nervous system by way of the 

 cranial nerves, by way of the sacral nerves, or by way of the 

 spinal nerves to the sympathetic system. All of these fibres I take 

 to be pre- ganglionic fibres. And I think that any pre-ganglionic 

 fibre is capable, in proper conditions, of becoming connected with 

 any nerve cell with which a pre-ganglionic fibre is normally con- 

 nected ; although apparently this connexion does not take place 

 with equal readiness in all cases. On the whole it appears to me 

 that the functions exercised both by pre-ganglionic and by post- 

 ganglionic fibres depend less upon physiological differences than 

 upon the connexions which they have an opportunity of making 

 during the development of the nervous system and of the other 

 tissues of the body. 



A fuller account of the observations will be published in the 

 'Journal of Physiology,' after some further experiments have been 

 made. 



" Eesearches in Vortex Motion. Part III. On Spiral or Gyro- 

 static Vortex Aggregates." By W. M. Hicks, F.R.S. 

 Received January 12, — Read February 3, 1898. 



(Abstract.) 



A portion of the communication (Sect. II) extends the theory of 

 the simple spherical vortex discovered by Hill. The chief part 

 (Sects. I and III) refers, however, to a kind of gyrostatic aggregate. 

 The investigation has brought to light an entirely new system of 

 spiral vortices. To give an idea of the species of motion considered, 

 take the case of motion of an infinitely long cylindrical vortex of 

 sectional radius a. The velocity perpendicular to the axis inside the 

 vortex will be of the form v = f(r) where /(o) = 0. Outside it will 

 be given by v = Va/r where V = f(a). 



We may, however, have a motion in which the fluid moves parallel 

 to the axis inside the cylinder with rest outside. The velocity will 

 be of the form u = F(r) inside, where F(a) = 0, and zero outside. 

 Roth/(r) and F(r) are arbitrary functions subject only to the condi- 

 tions /(0) =0 and F(a) = 0. Putting aside for the present the 



