1862.] 247 



there are enlargements resembling ganglia, and that the hepatic 

 ducts and gall-bladder are largely supplied with these gangliform 

 plexuses of nerves, which all arise from the semilunar ganglion and 

 solar plexus." 



In a Postscript, received October 4, 1862, the author adds, that 

 from an elaborate dissection which he has made since the date of the 

 paper, " it is demonstrated 



" 1 . That the nerves of the liver take their origin from ganglia 

 situated around the root of the hepatic artery, which are intimately 

 connected with, or actually form a part of, the semilunar ganglion of 

 the great sympathetic. 



"2. That the hepatic nerves, thus originating, proceed to the 

 liver along with the hepatic artery, hepatic veins, the vena portse, and 

 the hepatic ducts. 



" 3. That the hepatic nerves, on reaching the liver, send nume- 

 rous branches to the different lobes, along with the ramifications of 

 the hepatic artery to every part of the organ, and that plexuses of 

 nerves accompany the most minute branches of the arteries. 



" 4. That the hepatic and cystic ducts are surrounded with 

 plexuses of ganglia and nerves, and that nerves accompany the 

 arteries of the gall-bladder throughout their distribution. 



" 5. That besides these nerves, accompanying the trunk and 

 branches of the hepatic artery and surrounding the cystic and 

 hepatic ducts, there is a great system of ganglionic nerves distributed 

 to the walls of the vena portse." 



V. " On the Volumes of Pedal Surfaces." By T. A. HIRST, 

 F.R.S. Received 28th August, 1862. 



(Abstract.) 



Since the term "pedal surface" has but recently been definitively 

 adopted*, it may be well to state that it indicates, simply, the locus 

 of the feet of perpendiculars let fall from a fixed point, the pedal 

 origin, upon all the tangent planes of a given surface. It is some- 

 times convenient, too, to regard the pedal surface as the envelope of 

 a sphere, whose diameter is the radius vector from the pedal origin 



* A Treatise on the Analytic Geometry of Three Dimensions. By George 

 Salmon, D.D. 1862. 



