232 INTERNAL SECRETION 



lowering blood-pressure is not due to a decreased cardiac activity, 

 but is the expression of a peripheral vasodilation. 



A similar gradual inversion of the characteristic action of 

 adrenalin is also seen in the case of other organs. The behaviour 

 of the uterus is entirely analogous. After moderately large doses 

 of ergot, the pregnant uterus will not contract in response either 

 to adrenalin or to stimulation of the hypogastric nerve ; on 

 the contrary, both methods produce considerable uterine relax- 

 ation. This applies to the rabbit and the ape. In the case of 

 the cat, stimulation of the sympathetic, whether direct or by 

 means of adrenalin, inhibits the movements of the virgin uterus, 

 while, in the pregnant uterus, it produces strong contraction. 

 Toxic doses of ergot do not alter the inhibitory action of adrenalin 

 upon the virgin uterus of the cat, but the pregnant uterus responds, 

 no longer by contraction, but by relaxation. 



The spleen which, under normal conditions, responds to 

 adrenalin by contraction, after ergot poisoning responds by 

 relaxation. The internal sphincter muscle of the cat, in which 

 the action of adrenalin normally produces contraction, likewise 

 relaxes under the toxic influence of ergot. The stimulatory effect 

 observed in the urinary bladder of the ferret, as the result either 

 of adrenalin or of irritation of the hypogastric nerve, becomes 

 inhibitory under the toxic influence of ergot. 



Acute ergot poisoning produces no change in the nature of 

 the results which follow stimulation of the cranial and sacral 

 autonomous nerves, or of the nerves supplying the skeletal 

 muscles. Stimulation of the vagus produces the customary effects 

 of inhibition of cardiac activity and contraction of the stomach, 

 intestine, and gall-bladder. Stimulation of the chorda tympani 

 provokes secretion of saliva ; and stimulation of the pelvic nerve 

 is followed by the customary contraction of the urinary bladder 

 and large intestine, and by dilation of the vessels of the penis. 

 After poisoning by ergot, the skeletal muscle contracts in 

 response to stimulation of its motor nerves in the same manner 

 as under normal conditions. It is evident, then, that the 

 inhibitory action of ergot is confined to the myoneural junctions 

 of the sympathetic system. 



A closer investigation shows, however, that this conclusion is 

 subject to certain modifications. The following table shows the 

 effects which adrenal has in stimulating the sympathetic nerves, 

 both under normal conditions and after large doses of ergot. 



The results which this table includes may be classified in 

 three groups : 



(1) Where the sympathetic innervation is exclusively 

 inhibitory, as in the stomach, intestines, urinary bladder, and 

 virgin uterus, ergot poisoning produces no change in the effects 

 brought about by adrenalin and by stimulation of the sympathetic. 



(2) Where the sympathetic innervation is exclusively stimu- 



