466 



SYMPATHETIC NERVE. 



cited by Volkmann, fed several frogs with 

 worms and immediately destroyed the spinal 

 cord : on opening the animal twenty-four 

 hours afterwards, the stomach was found 

 distended with tough slimy matters : if, on 

 the other hand, forty-eight hours were al- 

 lowed to elapse before the stomach was 

 examined, it was found almost empty, part 

 of the contents having been probably ab- 

 sorbed, while part had passed downwards 

 into the intestinal canal. The continuance 

 of the movements of the intestinal canal 

 after the brain and spinal cord have been 

 removed, would seem to indicate that these 

 are not the immediate centres on which their 

 contractions depend. The contractions which 

 take place may be explained as due to the 

 inherent irritability of the muscular fibres, 

 while their type may be said to be owing to a 

 peculiar arrangement of these, by which the 

 contraction of one bundle acts as a stimulus 

 to the neighbouring bundles, exciting these to 

 contraction also, and in this way giving rise to 

 the vermicular movements of the gut. It 

 seems probable, however, that they are re- 

 gulated by the ganglia of the sympathetic, 

 especially since it has been observed by 

 Henle*, that in pieces of the intestine which 

 have been cutaway close to the line of attach- 

 ment of the mesentery, the contractions pro- 

 duced by application of local stimuli extend 

 but a little way on either side of the point 

 irritated, and are comparatively feeble. When 

 a part of the mesentery is removed along with 

 the portion of the intestine, they are more 

 powerful and more extended, and are most so 

 when the intestine and mesentery are left in 

 their normal relations. 



Genito - urinary organs. Contractions of 

 the ureters have been frequently observed by 

 Valentin f to follow irritation of the abdo- 

 minal ganglia of the sympathetic. They pre- 

 sent the same peristaltic character as those 

 of the intestines, and pass downwards from 

 the kidney towards the bladder. In the 

 bladder contractions are more easily pro- 

 duced than in the ureters: sometimes shortly 

 after opening the abdominal cavity of an 

 animal newly killed, the bladder contracts so 

 powerfully as to give rise to an expulsion of 

 its contents. Contractions may be excited 

 in it, according to Valentin, by irritation ap- 

 plied to the sympathetic cord in the abdomen 

 or pelvis, or to the lower lumbar and upper 

 sacral ganglia ; the contraction commonly 

 commencing on that side of the bladder on 

 which the nerves have been irritated. The 

 last lumbar and first sacral ganglia are de- 

 scribed by him as having most influence over 

 its movements. In the vas deferens powerful 

 contractions have been observed by Valentin 

 when stimulus was applied to the two last lum- 

 bar ganglia : the rabbit and guinea-pig were the 

 animals on which this experiment was made. 

 In the latter animal the vesicular scminales 

 were also excited to contraction by irritation 

 applied to the lower lumbar and upper sacral 



* Allgemeiue Anatomic, p. 724. 

 t Op. cit. p. 468. 



portions of the sympathetic, sometimes so 

 powerful as to expel the contents through 

 the opening of the urethra. Stimulus ap- 

 plied to the same parts in the female gives 

 rise to contractions in the Fallopian tubes. 

 The uterus may, according to the same ob- 

 server, be excited to contraction by stimulus 

 applied to the lower lumbar and upper sacral 

 ganglia, or to the branches given off" from 

 these. The contraction in such cases passes 

 downwards from the Fallopian tubes towards 

 the vagina. 



In regard to the influence of the central 

 parts of the nervous system over the move- 

 ments of these organs, it would appear, from 

 Valentin's experiments, that contractions 

 may be excited in the urinary bladder by 

 stimulus applied to the spinal cord. The 

 ureters are also said to exhibit contractions 

 when the wires of the magneto-electric appa- 

 ratus are brought into contact with the me- 

 dulla oblongata, or with the spinal cord in 

 the cervical or thoracic regions, as also when 

 they are applied to the right optic thalamus. 

 The same also holds true, according to him, 

 regarding the vasa deferentia, Fallopian tubes, 

 and uterus. He has further observed, that 

 often when the stimulus is applied to one 

 side of the central nervous masses, it is the 

 organ on the opposite side which is excited 

 to contraction : thus stimulus applied to the 

 right optic thalamus not unfrequently acts on 

 the ureter of the left side ; in like manner, 

 when the right hemisphere of the cerebellum 

 is the part irritated the contractions some- 

 times take place in the Fallopian tubes or 

 vas deferens of the left side. 



These organs, however, like those already 

 mentioned, exhibit their usual contractions 

 after they are removed from the influence of 

 the brain and spinal cord. The fact that in 

 paraplegic women delivery has taken place, 

 would appear to show that the contractions 

 of the uterus are not dependent upon the cen- 

 tral masses of the nervous system : this is also 

 shown by an experiment of Segalas*, that di- 

 vision of the spinal cord in the lumbar region 

 in the rabbit does not prevent the completion 

 of the labour. Moreover, it would appear, 

 from a series of experiments made by Pro- 

 fessor Simpson of Edinburgh, that the whole 

 process of labour may be completed, although 

 the spinal cord has, in great part, been pre- 

 viously removed. 



Pupil. It was long ago ascertained by 

 Pourfour du Petit-]-, that section of the 

 main cord of the sympathetic in the neck 

 is very quickly followed by contraction of 

 the pupil, besides certain other phenomena. 

 The same experiment has since been made 

 by Molinelli, Dupuy, Reid, Valentin, and 

 others. Molinelli regarded the effect pro- 

 duced upon the pupil not as an immediate 

 effect of the operation, but as an after result ; 



* Bulettin de 1'Acaclemie dc Medicine, torn. ix. 

 p. 1124. 



j- Histoire de 1'Academie, 1727, 1729, Paris, p. 5. 

 et seq. 



J See Budge, in Vierordt's Archiv. fiir physio- 

 logiscke Heilkunde, 1852, Erganzungs Ileft. 





