470 



SYMPATHETIC NERVE, 



that no reflex action could be produced in 

 the voluntary muscles. The heart was then 

 laid bare, and during an interval of 101 minutes 

 its pulsations were counted at fourteen dif- 

 ferent times. Five minutes after destruction 

 of the central organs they numbered 72 per 

 minute ; thirty minutes afterwards they were 

 48 per minute. After this they were found 

 to average between 45 and 51 per minute. 

 He then crushed with the blow of a hammer 

 one of the hind feet ; and now, during the 104th 

 minute after the spinal cord had been de- 

 stroyed, counted 70 pulsations. Thus, then, 

 two hours after the operation of destroying 

 the spinal cord, we have a sudden increase of 

 20 beats in the minute, which admits of hardly 

 any other explanation than that given by 

 Volkmann, that it was due to the stimulus ap- 

 plied to the foot being reflected to the nerves 

 of the heart through the ganglia of the sym- 

 pathetic. 



Influence of the sympathetic on the vegetative 

 processes. According to some, these pro- 

 cesses go on independently of any influence 

 exercised by the nervous system, while others 

 maintain that the two are more or less in- 

 timately connected. Of the latter some believe 

 that the sympathetic is the only part of the 

 nervous system by which such influence is 

 exercised, while others hold that it exercises 

 no influence in this respect which is not also 

 exercised by the cerebro-spinal system. 



There can be no doubt that in the plant 

 the processes of nutrition take place without 

 the co-operation of any nervous influence; 

 and in the same way in the embryo of all 

 animals they go on for some time before any 

 trace of nervous tissue has appeared. In 

 the animal after birth, however, they appear 

 to be more or less influenced by the nervous 

 system. This is rendered probable by several 

 circumstances, such as the effects of various 

 powerful mental emotions and of morbid states 

 of the nervous system upon digestion, on the 

 secretion of the saliva, tears, &c. ; the effects 

 of the same upon the heart and capillary 

 vessels. This is also shown by the changes 

 which take place in the nutrition of parts, 

 when the nerves by which they are supplied 

 have been divided, or after lesions of the 

 brain or spinal cord. Thus, as shown by 

 Magendie, section of the fifth nerve is very 

 quickly followed by distension of the blood- 

 vessels and inflammation of the conjunctiva, 

 sclerotic, and other parts of the eye, which 

 may terminate, in the course of two or three 

 weeks, in complete disorganisation of the 

 eyeball. It has also been found that sec- 

 tion of the nerves of a broken limb prevents 

 the due formation of callus. The experi- 

 ments of l)rs. Sharpey and Baly on the 

 salamander also prove that parts are repro- 

 duced much more slowly and less perfectly 

 when the spinal cord has been destroyed to 

 a certain extent than under opposite circum- 

 stances. When wounds are inflicted upoo 

 both limbs of an animal, and the nerves of 

 the one limb are divided while those of the 

 other limb are left entire, it has been found 



that while a lively inflammation and normal 

 suppuration take place in the wound of the 

 limb the nerves of which have been left en- 

 tire, the wound in the limb whose nerves 

 have been cut scarcely inflames at all, and 

 only a thin unhealthy discharge is formed. 

 Lesions of the spinal cord have also been 

 observed to be followed sometimes by morti- 

 fications of the paralysed limbs, and this with 

 such rapidity as would seem to indicate that 

 they stand to one another in the relation of 

 cause and effect. The tendency to sloughing 

 observed in typhus and other diseases at- 

 tended with great depression of the functions 

 of the nervous system would also seem to 

 indicate connection between the nutritive pro- 

 cesses and the nervous system. 



It has been already noticed that branches 

 of the sympathetic pass along with the arte- 

 ries in considerable numbers ; some of them 

 being apparently distributed to their coats, 

 while others accompany them into the sub- 

 stance of the different glandular organs. It 

 has also been stated that sympathetic fibres 

 have been observed to join the cerebro-spinal 

 nerves, and to run peripherically with them to 

 the different organs of animal life. From this 

 distribution of the sympathetic, it has been 

 held that it is in a peculiar manner connected 

 with the nutritive processes. That it does 

 exert an influence over the nutritive pro- 

 cesses is seen from the effects which follow 

 division of its branches. In addition to con- 

 traction of the pupil section of the sympa- 

 thetic in the neck has also been observed to 

 be followed by a disturbed state of the cir- 

 culation in the eyeball, giving rise to swelling 

 and inflammation of the cornea, a shrinking 

 of the eyeball, and at the same time to an 

 increase in the lachrymal secretion. In some 

 of the experiments of Dr. John Reid, the in- 

 jected state of the conjunctiva took place in 

 the course of a few minutes after the opera- 

 tion. In a dog, in which he had divided the 

 common trunk of the vagus and sympathetic 

 as high up as possible, Valentin * observed 

 that the secretions of the eye were very much 

 increased, remaining so even after the lapse 

 of several months. The same effects were 

 also observed by him after extirpation of the 

 superior cervical ganglion in the same animal. 

 Dupuy found, on removing the superior cer- 

 vical ganglion of both sides in the horse, that 

 besides the effects above described the opera- 

 tion was followed by an anasarcous condition 

 of the limbs and an eruption on the whole 

 cutaneous surface. 



Schifff found, when the two upper tho- 

 racic ganglia in the dog or rabbit were re- 

 moved, that the animal did not survive the 

 operation for more than thirty-four hours; 

 the heart, in the meantime, pulsated very 

 quickly and forcibly. On examination after 

 death, the blood-vessels of the pericardium 

 were observed to be distended with blood, 



* Op. cit. p. 423., as quoted by Longet. 

 f De vi motoria basics encephali, p. 37., as quoted 

 by Valentin. 



