114 Mr Roy, On the mechanism of the renal secretion. [May 23, 



9. Stimulation of nearly all the roots of the splanchnic in the 

 thorax, and of both larger and smaller splanchnic nerve-trunks 

 causes contraction of the kidney of the opposite side. 



The extent to which the kidney contracts on stimulation of the 

 splanchnic is usually very considerable. In one case the kidney 

 contracted on stimulating with a strong induced current for three 

 minutes to an extent which was equal to 63 per cent, of the post- 

 mortem volume of the organ. 



10. In nearly ever}'' case stimulation of the peripheral end 

 of the cut splanchnic at the point where it passes through the 

 diaphragm causes contraction of both kidneys ; the kidney of the 

 side opposite to the nerve stimulated commencing to contract 

 later than the one on the same side as the stimulated nerve. 



11. Stimulation of the central end of a sensory nerve, or of 

 the medulla oblongata, or of the cervical spinal cord, causes a 

 contraction of the renal vessels after both splanchnics have been 

 cut at their point of entrance into the abdominal cavity. 



Vaso-constrictor influences may therefore pass from the spinal 

 cord to the kidney by some other path than the two splanchnics. 



12. Section of the splanchnic does not always cause an ex- 

 pansion of the renal vessels, a fact which would make it doubtful 

 whether a vascular tonus of the renal vessels emanating from the 

 vasomotor centre or centres in the spinal cord is normally present. 



13. Stimulation of the central ends of the majority of the 

 fine nerves which enter the kidney along with the vessels causes a 

 contraction of the vessels of the kidney. 



14. Stimulation of the peripheral end of each and all of the 

 renal nerves which accompany the vessels causes a contraction of 

 the organ. 



15. After section of all but one of the (usually from 7 to 11) 

 nerves accompanying the renal vessels, stimulation of the jDeripheral 

 end of the splanchnic or of a sensory nerve still causes a contrac- 

 tion of the kidney which differs but little in amount from- that 

 produced by the same stimulation when all the renal nerves were 

 intact, but which takes longer time to shew itself after the stimu- 

 lation. 



16. The latent period between the commencement of the 

 stimulation and the contraction which it produces may vary greatly 

 in different individuals and in the same individual under different 

 conditions. 



17. Great differences may exist in the length of the latent 

 period according to the strength of the stimulation employed, but 



