THE SUPRARENAL SYSTEM 23! 



increased nor diminished, but represent the normal response. In 

 those organs, however, in which, in addition to a sympathetic, 

 there is also an antagonistic autonomous innervation, the result of 

 the specific action of adrenalin will be so marked an increase in 

 the strength of the sympathetic effects, that the autonomous inner- 

 vation will appear to be paralysed. Similar results are observed 

 after the simultaneous stimulation of the sympathetic and 

 autonomous nerves of any organ, the sympathetic effects, in this 

 case also, far outweighing those of the autonomous innervation. 

 In cases where, while the sympathetic is under the influence of 

 adrenalin, stimulation of the antagonistic autonomous nerve (vagus, 

 pelvic nerve) is without effect, the result is due, not to paralysis cf 

 the latter, but to a preponderance of the chemical over the electric 

 influence upon the nerve-terminals. Hence, as soon as adrenalin 

 ceases to act upon the sympathetic, electric stimulus of the 

 autonomous nerve produces the customary result. 



In the course of his investigations into the physiological 

 action of the ergot preparations, namely, cornutin (Kobert), 

 sphacelotoxin (Jacoby), chrysotoxin or ergotoxin (Dale), A. H. 

 Dale discovered certain remarkable departures from the known 

 method of action of adrenalin, to which a special interest attaches. 



The first effect produced by small quantities of the ergot 

 preparations is a stimulation of all the organs possessing 

 unstriated muscle structure. Such doses bring about contraction 

 of the blood-vessels and consequent increase in blood-pressure, 

 together with contraction of the uterus and of the sphincter muscle 

 of the iris. We have as yet no certain knowledge as to the site 

 of origin of this stimulatory action. Larger doses produce 

 progressive inhibition of the motor elements which were previously 

 stimulated. At this stage, adrenalin fails to effect either a rise 

 in blood-pressure or uterine contraction. A still further increase 

 in the size of the doses of ergot produces the paradoxical result, 

 that adrenalin in quantities which, in the first instance, effected an 

 enormous rise in blood-pressure and were negatived where the 

 ergot dosage was moderately increased, now bring about a fall 

 in blood-pressure, the degree and duration of which is propor- 

 tionate to the amount of adrenalin exhibited. In the same way, 

 a quantity of nicotine which at first increased the tension of the 

 vessels now diminishes it. Stimulation of the splanchnic nerve or 

 of the spinal cord, instead of producing the customary rise in 

 arterial tension, is followed by a fall. Moreover, substances such 

 as barium chloride, which, under normal conditions, exercise a 

 direct stimulatory action upon the involuntary muscles, are now 

 followed by a rapid increase in arterial tension ; while pituitary ex- 

 tract, the action of which is to raise blood-pressure, increases the 

 tension of the vessels in animals at the third stage of ergot 

 poisoning. 



It is, moreover, easy to prove that this effect of adrenalin in 



