Influence of Corpus lutcuni Kxiracts upon Plain Muscle 



17 



Taule Vlli.— UuiNEA-ria. 



Lani^ley and Anderson (13) showed that stimulation of the hypogastric 

 produces certain effects upon the uterus in the rabbit, but they failed to 

 get any result on stimulating the pelvic nerve. They concluded that the 

 hypogastric is the only nerve in the rabbit which influences utt-'rine con- 

 traction : and as corpus luteum generally produces the same effect in this 

 animal as adrenalin, which is known to operate through the sympathetic 

 nerve-endings, the conclusion is that the action is not through the pelvic 

 nerve, although it may be thi'ough the hypogastric (sympathetic). 



The effects produced by corpus luteum upon the uterus of the rat, cat, 

 and guinea-pig are the reverse of those which are produced by adrenalin ; 

 it therefore appears clear that the effect obtained is not that of the 

 sympathetic, although James and John Gunn (14) are of opinion that 

 at present there is no evidence that the sympathetic in the guinea- 

 pig and rat has an}^ motor fibres for the uterus. The result of my own 

 experiments, although showing that the action of corpus luteum extract 

 is not equivalent to that of adrenalin, affords no proof that it influences the 

 uterus through the mediation of sympathetic nerve fibres. Whilst, there- 

 fore, it is possible that the effect may be a direct one upon the muscular 

 fibres, I have not succeeded in devising experiments which are able to 

 determine this point. 



Effect upon the Excitability of the Vagus Nerve. 



I have made a few experiments to determine whether extract of corpus 

 luteum affects the excitability of either efferent or afferent fibres in the 

 vagus. Villemin (15) describes inexcitability of the vagus following 

 injection of corpus luteum extract, and his experiments were apparently 

 confirmed by Busquet (16). The latter, however, on reinvestigating the 

 subject along with Pachon, obtained uncertain results, and came to the 

 conclusion that there was no constant action upon the vagus nerve. In 

 my experiments the effects on carotid blood-pressure were used as an 

 indicator. In this way it was possible to observe the slowing of heart 

 VOL. XI. xo. 1. — 1917. 2 



