68 



THE NERVOUS SYSTEM 



nerves — those that constrict the vessels, and those 

 that dilate them. This view was finally established 

 in 1858 by Claude Bernard's experiments on the 

 chorda tympani and the submaxillary gland. 



The Lepns de Physiologie Opdratoire were 

 published in 1879. Twenty years later, Sir 

 Michael Foster says of Bernard's work : — 



"It is almost impossible to exaggerate the 

 importance of these labours of Bernard on the 

 vaso-motor nerves, since it is almost impossible to 

 exaggerate the influence which our knowledge of 

 the vaso-motor system, springing as it does from 

 Bernard's researches as from its fount and origin, 

 has exerted, is exerting, and in widening measure 

 will continue to exert, on all our physiological and 

 pathological conceptions, on medical practice, and 

 on the conduct of human life. There is hardly a 

 physiological discussion of any width in which we 

 do not sooner or later come on vaso-motor ques- 

 tions. Whatever part of physiology we touch, be 

 it the work done by a muscle, be it the various 

 kinds of secretive labour, be it the insurance of the 

 brain's well-being in the midst of the hydrostatic 

 vicissitudes to which the changes of daily life 

 subject it, be it that maintenance of bodily 

 temperature which is a condition of the body's 

 activity ; in all these, as in many other things, we 

 find vaso-motor factors intervening. And if, 

 passing the insecure and wavering line which parts 

 health from illness, we find ourselves dealing with 

 inflammation, or with fever, or with any of the dis- 

 ordered physiological processes which constitute 

 disease, we shall find, whatever be the tissue speci- 

 ally affected by the morbid conditions, that vaso- 



