554 



THE EXCRETION OF URINE 



The Influence of the Nervous System on the Excretion of Urine. In 



spite of numerous and repeated attempts to demonstrate that a nervous 

 mechanism governs the excretion of urine, no proofs which are above 

 criticism have been forthcoming. Stimulation of the splanchnic nerves 

 results in a diminution in the excretion of urine, probably because of a 

 diminution in the blood supply of the renal vessels owing to the vasocon- 

 striction. Stimulation of the vagus nerves below the level of the cardiac 

 branches has been said to result in the augmentation of the rate of urine 

 excretion (Asher and Pearce 12 ). The results are doubtful, however, since 

 there is no increase in the oxygen absorption under the above conditions 

 (Pearce and Carter 13 ). 



There is no doubt that the renalnerves profoundly affect the excretion 

 of urine, but that they do so directly is very improbable, since perfectly 

 adequate renal -function can be maintained in animals that have had the 

 kidneys entirely removed and then replaced. There are numerous re- 

 flexes that affect the rate of urine excretion by constriction of the renal 

 vessels. Injury to the bladder or ureter, abdominal injuries to the kid- 

 ney, or even cold applied to the skin, may result in incomplete suppres- 

 sion of the urine. 



