174 EXCRETION. 



Bernard, in following out his ideas with regard to the 

 mechanism of secretion, supposes that there are certain 

 nerves derived from the sympathetic system, the galvaniza- 

 tion of which will arrest the flow of urine ; and others, be- 

 longing to the cerebro-spinal system, called by him the 

 motor nerves of the gland, which, when galvanized, should 

 increase the flow of urine ; but the kidney, unlike the true 

 glandular organs, will continue to secrete for a time when 

 removed from all nervous influence. He has divided the 

 sympathetic nerves that penetrate with the blood-vessels 

 at the hilum, and galvanized them, producing an arrest of 

 secretion during the entire period of the galvanization. 1 

 With regard to the determination of the motor nerve of the 

 kidney, the experiments are not so satisfactory ; and while 

 there may be nerves capable of exciting the secretion of 

 urine, analogous to the motor nerves of the salivary glands, 

 this has never been actually demonstrated. 



The final effect of division of all the nerves going to the 

 kidney is very curious. The immediate effect of destruction 

 of these nerves is to increase largely the amount of blood 

 sent to the kidney, the organ then pulsating like an aneuris- 

 mal tumor. In experiments on this subject by Miiller and 

 Peipers, the flow of urine was sometimes arrested by divi- 

 sion of these nerves, but occasionally it continued. In these 

 observations, the nerves were destroyed by applying a liga- 

 ture tightly to the vessels as they enter at the hilum, includ- 

 ing every thing but the ureter. The ligature was then 

 loosened, so as to admit the blood, but the nerves were 

 bruised and destroyed. 3 We have just referred to the 

 observations of Bernard, in which the flow of urine was 

 temporarily increased by this operation. The secretion 

 of urine continues, however, for only a few hours. It then 

 ceases, and the nutrition of the kidney becomes profound- 

 ly affected, its tissue breaking down into a putrid, seini- 



1 BERNARD, Liquides de Vorganisme, Paris, 1859, tome ii., p. 163. 



2 MUELLER, Manuel de physiologic, Paris, 1851, tome i., p. 391. 



