418 FUNCTIONS OF THE NERVES. [ce. iii. 



the question arises whether the cutaueous nerves then affected 

 completely repel the blood from the cutaneous vessels, by con- 

 tracting them, to the inner vessels of the body? or whether, 

 the heart disturbed at the time and not contracting, ceases for 

 a moment to impel the blood to the surface of the body, the 

 cutaneous vessels acting at the same time as in fainting, and by 

 virtue of their own elasticity repelling the blood to the internal 

 organs ? Often if one kidney be affected with calculus, or in- 

 flammation, a true ischuria comes on, for the other kidney, 

 although healthy, ceases to secrete urine. Physicians are aware 

 that this takes place from sympathy of the nerves of the two 

 kidneys. Do the renal nerves in this case drive away and repel 

 the blood that comes to the kidneys to be subservient to the 

 secretion of urine ? or do they not rather totally prevent the 

 secretion from the blood by causing spasm of the secreting ves- 

 sels? Truly, although there are numerous facts which teach 

 us that a stimulus may cause the fluids to be drawn to a 

 locality, there is hardly one to show that the nerves have the 

 opposite property of repelling the fluids. 



SECTION V. HAVE THE NERVES ANY INFLUENCE IN SECRETION ? 



In considering the causes which operate in producing such 

 varied secretions from the same blood, Boerhaave does not 

 detail how great a share the nerves may have in that function 

 of the animal economy.^ The illustrious Haller, in his notes to 

 the lectures of Boerhaave,^ conjectures that the nerves operate 

 in the secretion of the fluids, since they surround the vessels 

 of the viscera like sphincters, and thus either delay or pro- 

 mote secretion. It has already been stated why tliis eminent 

 man withdrew the doctrine as to the sphincters and loops of 

 the nerves, but he shows that the secretions and excretions 

 have a close connection with the nerves, when he treats on 

 the greater or less irritability of the excretory ducts.^ The 

 celebrated Tissot also devotes an entire section of his work on 

 the functions and diseases of the nerves, to the secretions, for 

 the purpose of demonstrating how much these latter are de- 

 pendent on nervous influence. 



» Instit. Med., Nro. 253. » Note (14) vi. 



' De Part. Corp. Hum. Fabr. et Ubu, lib. vii, sect, iii, § xii. 



