270 Mr. J. S. R. Russell. On the Nerve Roots of 



paralysis of certain muscles, if my observations with, regard to the 

 representation of muscles in the nerve roots are correct; whereas 

 section of alternate roots, while causing paresis of more muscles, can- 

 not produce paralysis of any one, the tensor fasciae femoris being 

 excepted. Such division of one or more nerve roots does not result 

 in incoordination of the remaining muscular combinations repre- 

 sented in other nerve roots ; the remaining movements are merely 

 more feeble. 



Exclusion of a certain Root or Roots during an Epileptic Spasm in the 



Limb. 



Division of one or more nerve roots produces alteration of the posi- 

 tion of a limb during an epileptic spasm, which altered position de- 

 pends on the muscular combinations that have been thus thrown out 

 of action. And the effect is identical when the root or roots are 

 divided at the time that the convulsions are evoked, and when they 

 have been divided some weeks previously, i.e., the position assumed 

 by the limb on one side of the body in which the root or roots are 

 divided previously is identical to that assumed by its fellow of the 

 opposite side, the root or roots of which are divided at the time that 

 the convulsions are induced. No incoordination is produced in the 

 action of the remaining muscular combinations ; and there is no 

 evidence of overflow of the impulses which ought to travel down the 

 divided root into other channels through the spinal centres so as to 

 reach the muscles by new paths. 



LIST OF PKEYIOUS EXPERIMENTAL RESEARCHES ON THE 

 LUMBO-SACRAL PLEXUS. 



PANIZZA, c Annali Universal! di Medicina,' 1834. 



MULLEB, 'Handbuch der Physiologic des Menschen,' vol. 2, 1834, p. 685. 



VAN BEEN, ' De Differentia et Nexu inter Nervos Vitse AnimaUs et Organisxni,' 



Leyden, 1834. 



KBONENBEBG, ' Plex. Nerv. Struct, et Virt.,' Berol, 1836. 

 ECKHABD, ' Zeit. f . rat. Med.,' vol. 7, p. 306, 1849. 

 PETEE, ' Arch, f . rat. Med.,' II, vol. 4, pp. 67, 77. 

 KBAUSE, ' Beitrage zur Neurologic der Oberen Extremitat,' 1865. 

 FEBBIEB AND YEO, ' Roy. Soc. Proc.,' vol. 32, 1881, p. 12. 

 PAUL BEET AND MAECACCI, Soc. de Biol., July 29, 1881 j also ' Lo Sperimentale/ 



Oct., 1881. 

 FOBGUE, ' Distribution des Racines Motrices dans les Muscles des Membres,' Mont- 



pellier, 1883. 

 SHEBBINGTON, ' Journal of Physiology,' vol. 13, No. 6, p. 621. 



DESCRIPTION OF FIGURES. 



FIG. 1. From a photograph of the most common type of lumbo-sacral plexus 

 met with in Macacus rhesus. Shows the lumbo-sacral cord, the nerve roots which 



