MODIFICATIONS OF SECRETION. 29 



are also subject to considerable modifications. A few years 

 ago, indeed, there was considerable discussion regarding a 

 subdivision of the reflex system of nerves, which was supposed 

 to preside over secretion, and was called the excito-secretory 

 system. The facts which led to the description of this sys- 

 tem of nerves had long been observed ; and they simply il- 

 lustrated the production of secretion in response to irritation. 

 Dr. H. F. Campbell, of Augusta, Georgia, published, in 

 185T, an essay on the excito-secretory system of nerves, 

 which received the prize of the American Medical Associa- 

 tion for that year ; 1 and a few months later, the same idea 

 was put into shape by Dr. Marshall Hall, who, however, yield- 

 ed the priority to Dr. Campbell. To Dr. Campbell certainly 

 belongs the credit of proposing the theory that the sympa- 

 thetic system presides over secretion ; but in this he only rea- 

 soned from the old experiments of Pourfour du Petit and 

 others, and failed to give any satisfactory physiological de- 

 monstration of his views. 



In 1852, five years before the publication of Dr. Camp- 

 bell's essay, in the course of his researches on the secretions 

 of the different salivary glands, Bernard pointed out the 

 reflex character of the act of secretion, and demonstrated 

 experimentally the influence of certain nerves upon the dis- 

 charge of fluid from the duct of the submaxillary. These 

 experiments were the first to give a clear idea of the action 

 of the nervous system upon secretion, and they have been 



1 CAMPBELL, Essays on the Secretory and the Excito-secretory System of Nerves 

 in their ^Relations to Physiology and Pathology, Philadelphia, 1857 ; also, Trans- 

 actions of the American Medical Association for 1857. 



In 1850, Dr. Campbell published in the Southern Medical and Surgical Jour- 

 nal an Essay on the Influence of Dentition in producing Disease ; in which he re- 

 marked the fact, that during dentition, the irritation in the mouth frequently in- 

 duced, in addition to the usual increase hi the salivary secretions, an increased 

 action of the kidneys and the mucous membrane of the intestinal canal. He 

 states that " this increase and change in the secretion are effected by the agency 

 of the altered function of the nerve upon the arteries from which these secre- 

 tions are eliminated." Dr. Campbell supposed that the nerves through which 

 these operations took place belonged to the sympathetic system. 



