CIRCULATION. 207 



Kidney} — The vasomotor nerves of the kidney leave the cord from the 

 sixth dorsal to the second lumbar nerve. In the dog, most of the renal vaso- 

 motor fibres are found in the eleventh, twelfth, and thirteenth dorsal nerves. 

 The stimulation of the nerves entering the hilus of the kidney between the 

 artery and vein causes a marked and sudden renal contraction, hut the organ 

 soon regains its former volume. Constriction follows also the stimulation of 

 the peripheral end of the cut splanchnic nerve. Bradford has demonstrated 

 renal vaso-dilator fibres for certain nerves by stimulating at the rate of one 

 induction shock per second. For example, the excitation of the thirteenth 

 dorsal nerve with 50 to 5 induction shocks per second gave always a constric- 

 tion of the kidney, but when a single shock per second was employed, the 

 kidney dilated. If the cells connected with the renal vaso-motor fibres are 

 stimulated directly by venous blood as in asphyxia, the animal being curarized, 

 a decided constriction of the kidney results. The reflex excitation of these 

 cells is of especial importance. The stimulation of the central end of the 

 sciatic or the splanchnic nerves causes renal constriction. The same effect is 

 easily produced by stimulating the skin, for example, by the application of 

 cold. The stimulation of the sole of the foot in a curarized dog caused 

 contraction of the renal vessels. There is some evidence that the 

 splanchnic vaso-motor fibres for the kidney end in the cells of the renal 

 plexus. 



Spleen. — The stimulation of the peripheral end of the splanchnic nerves 

 causes a sudden and large diminution in the volume of the spleen/ It 

 is, however, not certain whether the constriction of the spleen is to be 

 referred primarily to a constriction of its blood-vessels or to the contraction 

 of the intrinsic muscular fibres which play so large a part in the changes of 

 volume of this organ. The doubt is strengthened by the fact that section of 

 the splanchnic nerves does not alter the volume of the spleen ; dilatation 

 would be expected were these nerves the pathway of vaso-constrictor fibres 

 for the spleen. 



Pancreas. — Francois-Franck and Hallion find vaso-constrictor fibres in 

 the sympathetic chain between the sixth and eleventh ribs; they leave the 



spinal cord from the fifth dorsal to the second lumbar ramus ( imunicans, 



pass into the greater and lesser splanchnic nerves, and reach the gland along 

 the pancreatic artery. A few dilator fibres were found in the sympathetic ; 

 more in the the vagus.' 5 



Externa/ Generative Organs/ — The recent history of the vaso-motor nerves 

 of the external generative organs— namely, those developed from the urogenital 

 sinus and the skin surrounding the urogenital opening — begins with Eck- 



1 Wertheimer : Archives de Physiologic, 1894, p. 308; Baylisa ami Bradford: Journal of 

 Physiology, 1894, \vi. p. 17. 



"Schaferand Moore: Journal of Physiology, 1896, xx. p. 1. 



3 Franck and Hallion: Archives de Physiologie, L896, pp. 908,923. 



*Franck: Archives de Physiologie, 1895, p. 122; Langle; and Anderson: Journal of Physi- 

 ology, 1895, six. p. 76. 



