“The laying bare of the spinal cord, and its free exposition to the action of the atmosphere, instead of being a cause or loss or diminution of sensibility, as it had been said, seems to be followed by a marked increase of sensibility in the parts of the body which are behind the place where the cord is exposed.… Deep injuries to the posterior columns of the spinal cord are always followed by a degree of hyperæsthesia greater than after the laying bare of the nervous centres--hyperæsthesia which appeared in all parts of the body behind the place injured.… Before the operation in rabbits the most energetic pinching of the skin produces agitation but no shrieking; after the operation, on the contrary the least pinching produces shrieking and a much greater agitation. Sometimes the hyperæsthesia is so considerable that the least pressure upon the skin makes the animal shriek. Whether the operation is performed on the lumbar, the dorsal, or the cervical region, the phenomena are always the same--that is, there is manifest hyperæsthesia in the various parts of the body which receive their nerves from the part of the spinal cord which is behind the section. It has been so in all the animals I have operated upon, and I have already made this experiment upon animals belonging to more than twenty species. As long as the animals live after the section of the posterior columns, hyperæsthesia continues to exist, except in the cases where re-union takes place between the two surfaces of the section; but hyperæsthesia is greater during the first week after the operation than it is after a month or many months.”--_Brown-Séquard_, “_Lancet_” 1,823 and 1,819. M. Brown-Séquard has devoted his time since his graduation almost exclusively to experimental investigations on physiological topics, especially on the spinal column, the muscular system, the sympathetic nerves and ganglions, and on the effect of the removal of the supra-renal capsules, &c. Author of many Essays and Papers giving details of his Experiments. =Bruns, Paul Victor.= B. in Helmstedt, 1812. Stud. Tübingen, 1833; M.D., 1837; Prof. Anat. College, Brunswick, 1839; Prof. Surg., Tübingen, 1840. Author of “Handbuch der practischen Chirurgie,” Tübingen, 1854-60; “Chirurgische Atlas,” Tübingen, 1853; “Die Durchschneidung der Gesichtsnerven,” Tübingen, 1859; “Die Behandlung schlechtgeheilte Beinbrüche,” Berlin, 1861; “Die erste Ausrottung eines Polypen in der Kehlköpfröhre,” Tübingen, 1862; “Die Laryngoskopie,” Tübingen, 1862; “Chirurgische Heilmittellehre,” Tübingen, 1868-73; “Arznei-operationen,” Tübingen, 1869; “Die Galvano-Chirurgie,” Tübingen, 1870.