510 



A TEXTBOOK OF PHYSIOLOGY 



sympathetic system, and in every case produces the same effects as does 

 excitation of the sympathetic nerves (see Figs. 246, 247 ). It is probable 

 that this action is manifested through the '* receptive substance " 



FIG. 244. TRACING SHOWING EFFECT ON CAROTID PRESSURE OF ANESTHETIZED 

 l)oc BY INTRAVENOUS INJECTION AT SIGNAL OF AN EXTRACT FROM THE CHROMO- 

 PHIL BODIKS OF THREE DOGS. 



FIG. 245. PITHED ANIMAL. (T. K. Elliott.) 



A Effect of stimulation of both splanchnic nerves; 118 mm. Hg rise of pressure. 

 B, Ditto, after removal of intestines; 48 mm. rise of pressure. C, Ditto, after 

 removal of suprarenals; no rise of pressure. 



which effects the union between the sympathetic nerve fibre and the 

 smooth muscle. This receptive substance depends for its action upon 

 the integrity of the muscle rather than upon the integrity of the nerve 



