548 ACONITE 



shown by the blood of a poisoned dog, five minutes after the 

 drug has been administered, being transferable into the 

 veins of another dog without producing the physiological 

 action of the poison. 



Full medicinal doses administered by the mouth induce 

 salivation, champing of the jaws, movements of swallowing, 

 and nausea, and cause in dogs and cats vomiting, and in 

 horses, ruminants, and rabbits retching and eructation of 

 frothy mucus. The topical irritant action is exerted not 

 only on the stomach, but sometimes on the bowels, which 

 are affected by spasms and diarrhoea, while the secretions of 

 the skin and kidneys are also increased. Within fifteen to 

 twenty minutes the strength and frequency of the heart- 

 beats are reduced, and blood-pressure is lowered. These 

 effects on the circulation appear to depend upon the in- 

 hibitory action of the vagus due to stimulation of the vagus 

 centre in the medulla. This can be proved experimentally 

 by cutting the vagi when the heart resumes its normal rate 

 and strength. The vaso-motor centre is also probably 

 stimulated at the same time, but the cardiac depression is 

 such that the blood-pressure falls. From the impaired 

 circulation temperature is lowered, and general muscular 

 weakness ensues. There is some evidence to show that 

 aconitine acts to some extent on the heat-regulating centres 

 in the brain. Kaufmann records that subcutaneous injec- 

 tion of aconitine, in moderate doses in dogs, lowered 

 the temperature from 38* 5 Cent, to 36*7 Cent. ; while 

 intravenous injection in horses reduced the temperature from 

 37-4 Cent, to 37' 1 Cent. Partly from the reduced circula- 

 tory force, and partly from the drug directly depressing the 

 respiratory centre, breathing is slow and deepened, and 

 exhibits a distinct expiratory effort. When large or re- 

 peated doses have been given, aconite exerts a direct action 

 on the heart muscle, lessening its power of conducting 

 impulses from auricle to ventricle. Thus the contractions 

 of the auricles and ventricles are independent and arhythmic, 

 cardiac action becomes irregular, and often much quickened, 

 but tension remains low (delirium cordis) ; the breathing 

 becomes still slower, shallower, and more laboured ; after 

 every two or three respirations there is a distinct pause in 



