THE SKIN AND COMMON SENSATION. 979 



Turner, 1 believe that pain impulses cross almost immediately after entrance into 

 the cord, and pass up the opposite half of the spinal cord. Miescher 2 and Woros- 

 chiloff 3 arrived at the result that, in the rabbit, the impulses ascend the lateral 

 columns, and I 4 obtained the same result in the dog, using blood pressure 

 reflexes as sign. Weiss, 5 Homen, 6 Osawa, 7 Mott, 8 Bottazzi, 9 and Holtzinger 10 

 conclude the conduction involves both lateral columns, the tautomeric about as 

 much as the crossed. In al 1 this experimental work on animals the observer 

 has to work through signs of subjective states incomparably inferior in most 

 instances to the verbal communication establishable with an intelligent human 

 subject. Clinical pathology, therefore, can render great service here. 



Yieusseux n a Swiss physician (1818), suffering from spinal disease noted 

 with surprise that the fingers of his right hand, though analgesic to such 

 degree that they bore without pain any degree of pressure or wounding, could 

 feel and judge a patient's pulse quite well. Since then, especially since E. H. 

 Weber's researches, 12 many cases of " dissociation " paralysis of the skin, have 

 been observed as the result of spinal diseases, including pressure lesions, traumatic 

 injuries, syringoniyelia, tabes dorsalis, leprosy, etc. In certain stages of ether 

 narcosis a similar phase of dissociative paralysis occurs. 13 



This sundering of the different species of skin sensations one from another 

 in spinal disease, most frequently takes the form of partial, often severe, im- 

 pairment of the pain and thermal sensation, while tactual remains normal or 

 nearly so. Mechanical stimuli are felt by the skin with normal delicacy as 

 " touches," while stimuli that normally are painful are felt merely as touches. 

 This, I find, occurs at the edge of an isolated spinal root skin field. It also 

 occurs in diseases of the spinal grey matter (e.g. syringomyelia, gliosis). 



In these latter it forms, with certain features of distribution, a pathogno- 

 monic condition. Contact with the finger-tip, a brush, the head of a pin, is 

 normally perceived and properly localised ; but with this may coexist complete 

 analgesia, to mechanical as well as thermal irritants. The patient no longer 

 feels a pin-prick or a strong faradic current as pain. Ability to distinguish 

 differences of temperature may be totally gone. The sense of pain of the deeper 

 parts is also impaired, so that fractures of the bones are no longer felt to be 

 painful, and extensive surgical operations can be performed on the patient without 

 pain. The mucous membranes often participate in the impairment of temperature 

 sense, so that patients may eat too hot food without noting its harm. Careful 

 observation of the exact size and position of the lesion in the cord producing 

 this condition gives the following indications as to the position of the pain- 

 path. Certain cases 14 seem to prove pretty clearly that destruction limited to 

 one dorsal (posterior) grey cornu in a segment of spinal cord entails loss of sensa- 

 tion for pain (and temperature) in the corresponding segmented skin field (not a 

 peripheral nerve field) on the same side of the body. Instances show that 

 where both dorsal grey horns have been injured, but one more than the other, 



1 Brain, London, 1891, vol. xiv. p. 496. 



2 Arb. a. d. physiol. Anst. zu Leipzig, 1870, S. 172, 3 Ibid., 1874, S. 99. 



4 Sherrington, Brain, London, 1886, vol. ix. p. 342. 



5 Sitzungsb. d. k. Akad. d. Wissensch., Wien, 1879, Bd. Ixxx. Abth. 3. 



6 Compt. rend. Soc. de biol., Paris, 1883, p. 23. 



7 Thesis, Strassburg, 1882. 



8 " Proc. Physiol. Soc.," 1891, Journ. Physiol., Cambridge and London; and Phil. 

 Trans., London, 1892, pp. 1-58. 



9 Centralbl.f. Physiol., Leipzig u. Wien, 1894 Bd., S. 530. 



10 Neurol. Centralbl. (original), Leipzig, 1894, S. 642. 



11 Mehlis, " Commentatio de morbis," etc., Gottingen, 1818. 



12 Wagner's "Handworterbnch," 1846, Bd. iii. S. 2, especially case reported on S. 520. 



13 Longet, Arch. ge"n. de med., Paris, 1847, tome Ixxiii. p. 374. 



14 Dejerine and Sottar, Compt. rend. Soc. de biol., Paris, 1892, tome i. p. 716; Rosso- 

 lymo, Arch. f. Psychiat., Berlin, 1890, Bd. xxi. S. 997 ; Furstner and Zacher, ibid., 1883, 

 Bd. xiv. S. 422; Oppenheim, ibid., 1893, Bd. xxv. S. 315; E. Asmus, " Ueber Syringo- 

 myelia," Biblioth. med., Cassel, 1893, Bd. c. S. 1 ; M. Laehr, Arch. f. Psychiat., Berlin, 1897, 

 Bd. xxviii. S. 773 ; H. Schlesinger, "Die Syringomyelia," Leipzig- Wien, 1895. 



