FUNCTIONS OF THE SPINAL CORD. 643 



regulated without sensorial excitement ( 90). And there is much reason 

 to'believe that certain of the movements of the stomach itself are in like 

 manner dependent upon its connection with the Medulla Oblongata ( 91), 

 although there is evidence that it possesses an independent motor activity 

 of its own. The movements of the Intestinal tube are unquestionably in- 

 fluenced by the Spinal Cord, although perhaps in some measure independ- 

 ent of it ( 92-93); and the sphincter which surrounds its orifice of egress 

 is undoubtedly placed under its guardianship, although partly subjected (in 

 Man) to the control of the Will. 1 The same may be said of the expulsor 

 muscles concerned in the act of Defecation ; and of the expulsors and sphincter 

 which effect and control the act of Urination (99). Looking, 2 again, at the 

 movements which are subservient to the Respiratory process, we find that all 

 those which are essential to its regular maintenance are performed through 

 the intermediation of the Spinal Axis alone; that the Will has only such 

 a limited power over them as to bring them into harmony with its other 

 requirements, as in the acts of vocalization and in extraordinary muscular 

 exertions ; and that the stimulus by which they are commonly maintained 

 does not even affect the consciousness, the "besoin de respirer" only becoming 

 sensible when the respiratory process is being imperfectly performed ( 294- 

 296). Not only are the ordinary respiratory movements performed through 

 this channel, but the aperture of the Glottis is regulated by it, in every- 

 thing that concerns the respiration ; and either by its spasmodic closure 

 against the entrance of unfit substances, or by the expulsor effort of cough- 

 ing which is excited by them when they do find their way into the air-pas- 

 sages, these passages are kept free from solid, liquid, or gaseous particles, 

 whose presence in them would be injurious. As the great centre governing 

 the force and frequency of the cardiac contractions, and the calibre of the 

 vessels throughout the system, the spinal axis exerts an influence that is 

 felt in every part of the body over the processes of secretion and of nutri- 

 tion. In the expulsion of the Generative products also, the reflex power of 

 the Spinal Cord takes an important share. Budge 3 has demonstrated the 

 existence of a genito-spinal centre (in rabbits) in that portion of the Spinal 

 Cord which lies opposite the fourth lumbar vertebra ; for on irritating this 

 part, contractions of the rectum, bladder, and vasa deferentia occurred. 

 The same effects are produced on irritating the ganglion of the Sympathetic 

 nerve lying on the fifth lumbar vertebra, which receives communicating 

 branches from this part of the cord ; and the influence of the nervi erigentes 

 and common puclendal nerves observed by Eckhard, on the erection of the 

 penis and emissio seminis, has been already fully detailed ( 276). The 

 muscular contractions which produce Emissio Semiuis are excito-motor in 

 their nature; being independent of the Will, and not capable of restraint by 

 it when once fully excited ; and being (like those of Deglutition) excitable 

 in no other way than by a particular local irritation. It has been shown by 

 experiment, and also by pathological observation, that the separation of the 

 lower portion of the Spinal Cord from the upper does not prevent these 

 movements from being excited, although the act is then unaccompanied 

 with sensation, which proves that sensation is not essential to its perform- 

 ance; on the other hand, the power of emission is annihilated by destruction 

 of the lower portion of the Spinal Cord, or by section of the nerves which 



1 See Masius's Rechorches Experimentales, Bulletin de 1'Academie Royale de Bel- 

 gique, " ^er. t. xxv, No. 3, 18(i8. 



2 SeeGoltz, Pfliigor's Archiv, 1873, p. 474; and Wernich, Centralblatt, 1873, p. 

 533. 



3 Comptfs Rendus do 1'Acad. dos Scien , 1858, p. 586; Physiologic, 1862, p. 14; 

 and Pfliiger's Archiv, 1872, Bd. vi, p. 309. 



