472 



SYMPATHETIC NERVE. 



The experiments of Walther on the frog 

 would also indicate that the circulation is 

 more or less influenced by the sympathetic.* 

 When the fibres which are sent by the sym- 

 pathetic to the nerves of the lumbar plexus 

 were divided, he found, on examining the 

 circulation in the web of the foot, that, al- 

 though at first undisturbed, it very soon 

 afterwards increased in rapidity. The ca- 

 pillaries appeared to be dilated, and contained 

 fewer blood corpuscles than corresponded to 

 their calibre ; the increase in their diameter 

 equalled from one sixth to one eighth of the 

 calibre of the vessel. After a time the ra- 

 pidity of the circulation again diminished, 

 and in some parts it became stagnant. 

 Bidder-)-, on the other hand, could not in 

 his experiments satisfy himself that any dila- 

 tation of the capillary vessels took place. 

 Walther, however, has performed the ex- 

 periment so frequently, and so uniformly 

 with the same result, that he regards the 

 dilatation of the capillary vessels as con- 

 stant. 



There are, moreover, certain experiments 

 made by Valentin which show that the 

 branches of the sympathetic which are dis- 

 tributed to the walls of the blood-vessels, 

 exercise an influence over their contractions. 

 Thus, when stimulus was applied to the tho- 

 racic portion of the sympathetic in the horse, 

 he observed that the thoracic aorta and tho- 

 racic duct diminished in calibre to a much 

 greater extent than could be attributed to 



blood due to paralysis of the blood vessels. Ber- 

 nard, on the other hand, believes that the phe 

 nomena are not due to the effects of paralysis of the 

 blood vessels, but 'are active ; they are of the same 

 nature as the vascular turgesence which arises in a 

 secreting organ when it passes from a state of repose 

 to an active discharge of function, and resemble 

 the afflux of blood, and increased sensibility around 

 a recent wound or foreign body in the living tex- 

 tures ; phenomena which are not due to mere para- 

 lysis of the arteries. 



The sympathetic is the only nerve section of 

 which is followed by an exaltation of temperature. 

 [Section of the fifth nerve Bernard found to be fol- 

 lowed by diminution of temperature on the corre- 

 sponding side of the head. When the facial nerve 

 was divided at its exit from the cranium, an eleva- 

 tion of temperature took place on the paralysed 

 side ; this was increased when the sympathetics on 

 the same side were also divided. If the facial was 

 alone divided then, after a feAV days, the tempera- 

 ture returned to an equality on both sides of the 

 face. The calorification produced by section of the 

 facial nerve Bernard attributes to the division of 

 sympathetic fibres which join the nerve during its 

 course through the temporal bone. He also found 

 that when the anterior or posterior roots of the 

 spinal nerves going to form the sacral plexus were 

 divided, the temperature was not increased but 

 diminished. See Monthly Journal of Med. Science, 

 March, 1854. Original paper in Gazette Medicale, 

 Janvier, 1854. 



Budge finds that removal of the portion of the 

 spinal cord termed by him the ciliospinal region, is 

 attended by an increase of temperature on the cor- 

 responding side of the head in the same manner as 

 when the sympathetic is divided in the neck. 



* Muller's Archiv. 1844, p. 448. 



f Henle and Pfeuffer's Zeitschrift, band iv. p. 

 353. 



the mere action of the atmospheric air. In 

 a newly killed young rabbit, in which the 

 part of the vena cava next the heart, as well 

 as the right auricle were pulsating, he found 

 on applying the wires of the magneto-electric 

 apparatus to the right ventricles, that all con- 

 traction in the vessel immediately ceased. 



Whatever influence the nervous system 

 exercises over the processes of nutrition, it 

 would seem that the sympathetic cannot be 

 regarded as the only nerve concerned : the 

 cerebro-spinal system also appears to share 

 therein. In addition to what has been al- 

 ready stated, p. 470., there are also other 

 facts which favour such a view. Thus Ma- 

 gendie found that, where the spinal cord was 

 divided in the region of the neck, a disor- 

 ganisation of the eyeball followed, similar to 

 that which ensues upon division of the fifth 

 nerve. SchifF* has observed that when the 

 cms cerebri or optic thalamus in the rabbit 

 was cut across, the secretions of the intestinal 

 canal become altered; the excrements are 

 slimy and mingled with blood ; the digestion 

 is interfered with, the animal, towards the end 

 of the first week, losing all appetite for food. 

 After death the mucous membrane of the 

 stomach and bronchi was found to be more 

 or less injected with blood, the former also 

 being softened. Similar appearances were 

 also observed in the upper half of the small 

 intestine. That, moreover, the influence ex- 

 ercised by the sympathetic over these pro- 

 cesses does not differ from that exercised by 

 the cerebro-spinal system, is indicated by the 

 circumstance that several glandular organs, 

 such as the mammary and salivary glands, 

 derive their nerves chiefly from cerebro-spinal 

 nerves. 



From the experiments of SchifF and others 

 it would appear, however, that the ganglionic 

 system of nerves is more intimately con- 

 nected with these processes than the strictly 

 cerebro-spinal nerves are. Thus, SchifF found, 

 in regard to the fifth nerve, that when it was 

 divided between the brain and Gasserian gan- 

 glion, the destruction of the textures of the 

 eyeball follow more slowly then when it is 

 divided between the ganglion and the eye. 

 In the frog, also, when the lumbar plexus was 

 divided, the animal continued for two or three 

 months without any disturbance being ob- 

 served in the nutrition of the limb ; but when 

 several of the lumbar ganglia were removed, 

 dropsical effusion into the abdominal cavity, 

 and inflammation of the peritoneum, ending in 

 the death of the animal, ensued in the course 

 oftwoweeks.f Axmann , as quoted by Va- 

 lentin, divided at their roots the nerves which 

 supply the posterior extremity in the frog, 

 but in no instance observed that the opera- 

 tion was followed by any disturbance in the 

 nutritive processes : wounds of the soft tex- 

 tures as well as of the bones healed as rapidly 



* De vi motoria basios encephali, p. 37., as 

 quoted by Valentin. 



t Op. cit. p. 37. 



f T Ganglioruni Systematis Structura peitiri 

 ejusque Functionibus. Berlin. 1K<1~. > MX 



