CHAP, xm.] CIRCULATION. 217 



nerve had paralysed the vessels, and that consequently vaso- 

 motory nerves existed, there was only a step, apparently easy, 

 to take ; and yet that step was not taken till our own day. The 

 priority of precise and well-interpreted observations and experi- 

 ments seems to belong to M. Schiff (1845). 1 In France, M. Cl. 

 Bernard, who appears to have been ignorant at that time of the 

 labours of his predecessor, was the first to give a theory of the 

 vaso-motory nerves complete, demonstrative, and based on well- 

 made experiments. 2 We have now to indicate, without restricting 



I ourselves to follow the chronological order, the typical facts and 

 their signification. 



The section of the sympathetic nerve in the neck, or rather 

 the outpl ucking of the higher cervical ganglion, causes the dilata- 

 tion of the capillaries of the cerebral pia mater, of the con- 



I junctiva, of the ear of the corresponding side, and so on. This 

 dilatation is accompanied by a very notable elevation of local 

 temperature (5, 10, 15 degrees), demonstrated for the pia mater 

 and the brain ; in short, by all the phenomena, of simple conges- 



i tion, without inflammation. A wound in the ear of the side thus 

 injured bleeds more rapidly and more abundantly. The blood in 

 the veins of the side affected contains more oxygen and less car- 

 bonic acid than the ordinary venous blood. The sensibility is at 

 the same time intensified. Analogous phenomena are observed 

 in all the organs whose sympathetic nerves are cut, the liver, the 

 eins, the lungs, the intestines, &c. 3 



This congestion is not inflammatory. It persists for days and 

 for weeks without modification, and we might without temerity 

 affirm that it results from a paralysis, if we merely relied on the 

 facts which we have just enumerated ; but,the counter-proof has 

 been made, and leaves no room for doubt. If, in a dog whose 



1 De Vi Motoria Baseos Encephali, Bockenhemii, 1845. 



2 Cl. Bernard, Influence du Grand Sympathique sitr la Sensibility et la 

 Calorification (Comptes Rendus de la Sotiett de Biologie, 1851). 



3 Vulpian, Lemons su/r les Nerfs Faso-moteurs, t. I., pp. 94, 95, 106, 112, 

 531, 561. 



