320 THE ACTION OF THE NERVES 



310. The action of the iieryes distributed to the 

 capillary vessels. — We have now to consider the oflBce 

 of the nerve-fibres distributed to the capillary vessels 

 which I have been fortunate enough to demonstrate 

 in the tissues of so many vertebrate animals, as to 

 leave no doabt that they are constantly present and 

 discharge a highly important office in connection with 

 general physiological changes going on in all paxts 

 of the organism. These nerve-fibres of the capillary 

 vessels are essential. If they are deranged or damaged 

 the healthy action of the tissue or organ involved is 

 no longer properly discharged, while if the nerve-fibre 

 be destroyed the nutrition of the tissues adjacent 

 to the capillary must suffer. If the nerve-fibres 

 distributed to the capillaries extending over a con- 

 siderable area be destroyed by disease or damaged 

 indirectly owing to changes having taken place in 

 the nerve-centres connected with them, serious de- 

 rangement of the function of the organ involved is 

 the result, and a diseased state immediately follows, 

 which may progTess quickly or Tery slowly until at 

 last much normal tissue, which cannot possibly be 

 replaced, is completely destroyed. In many organs 

 such changes will cut short life, either immediately 

 or after prolonged sufiering from progressive struc- 

 tural change. 



It is very desirable, therefore, to determine the 

 exact action of a nerve mechanism which plays so 

 highly important a part in man and the higher 

 animals in health and in disease. With tliis object 

 I propose now to consider what is the nature of the 

 work discharged and the way in which it is per- 

 formed by the nerves distributed to the capillaries, 

 the arrano:ement of which had been described. 



Are the nerve-fibres of the capillaries sensitive r — 

 Considering the arrangement of nerve-fibres in the 

 organs of sense, no one would be hkely to infer that 

 those distributed to capillary vessels were in any way 



