748 THE HARVEIAN ORATION. 



elusion that the ganglionic eentres of innervation for the entire 

 sympathetic system occupy but a small space at the base of the 

 brain, two strips to wit, one on each side of the median fissure in 

 the floor of the fourth ventricle ; of, in the rabbit, a length of about 

 four millimeters, beginning about four or five millimeters anteriorly 

 to the calamus scriptorius, and ending about one or two millimeters 

 behind the level of the corpora quadrigemina. The title of such a 

 book as Eulenburg and Guttmann's 'Die Pathologic des Sympa- 

 thicus auf Physiol ogische Grundlage ' (Berlin, 1873) is an en- 

 couragement to those who hope to see fruit arise from such 

 researches as these in the way of additions to our means for meeting, 

 or at -least understanding, human disease and suffering. 



It has long been known (Budge, 1855) that the sympathetic 

 nerves which supply the vessels of the head and iris do not pass 

 directly or by the shortest possible route to this their distribution, 

 but pass down the spinal chord for a greater or lesser distance, and 

 then turn outwards^ and pass from the anterior nerve-branches to 

 bend upwards^ much as the recurrent laryngeal nerve does. That 

 other vascular regions receive their vaso-motor supply by this 

 apparently circuitous and, till the history of development is taken 

 into consideration, paradoxical route, is from time to time being 

 demonstrated. Dr. Pavy, to whom I have already referred, many 

 years ago identified and mapped out one segment of the road along 

 which nerve-force passes to the liver and prevents or allows the 

 occurrence of diabetes. Further exploration of this route we owe 

 to Cyon and Aladoff ('Bulletin de TAcademie Imperiale des 

 Sciences de St. Petersbourg,' tom. xvi. p. 307 ; ' British Medical 

 Journal,^ December 23, 1871) ; and this same investigator, working 

 still in the same line of investigation, as it is in these days usually 

 necessary for an investigator to work if he will make himself a 

 name as a discoverer, has also shown us (Ludwig's ' Arbeiten/ 3rd 

 year, 1868) the track along which the vaso-motor nerves of the 

 anterior limbs pass, proving that these nerves pass down in the 

 spinal chord as low as the mid-dorsal region before leaving it to 

 turn upwards in the sympathetic chain to join the brachial plexus. 

 Of all the results, however, which have been attained to in the 

 line of experimentation now under consideration, those come to by 

 Brown-S^quard and demonstrated by him at the meeting of the 

 British Association held at Liverpool in 1870, and subsequently 



