, ACONITE 437 



lowered for this reason and because of the lessened hearts 

 action. In poisoning, the pulse is weak, irregular and inter- 

 mittent; first slow and then rapid. There is ultimately 

 paralysis of the peripheral vagi, heart muscle and its 

 ganglia, and the vasomotor centres. The heart is arrested 

 in diastole, but death immediately results from respiratory 

 failure. 



Nervous System. — The most striking effect of aconite 

 on the nervous system consists in loss of sensation 

 and temperature sense after large medicinal doses. This 

 phenomenon is due to depression of the sensory nerve 

 terminations, and possibly to depression of sensory percep- 

 tive centres in the brain, and sensory side of the cord. The 

 drug is not comparable with opium, since doses large enough 

 to produce a general anodyne action are dangerous. 



Poisonous doses of aconite cause loss of motor power 

 as well as loss of sensation. This latter effect follows 

 paralysis of the motor nerve endings and perhaps the spinal 

 motor tract. There is some disturbance of the brain, as 

 exhibited by occasional delirium and convulsions. The 

 latter are supposed to follow interference with the circula- 

 tion at the base of the brain. Furthermore, in man, dizzi- 

 ness, blindness, deafness and loss of speech sometimes occur 

 in lethal poisoning. 



Respiration. — ^The breathing of animals under the influ- 

 ence of aconite resembles that observed after section of the 

 vagi. The respiration is slow ; the expiration is prolonged, 

 and is succeeded by a considerable interval before the next 

 inspiration. This condition is brought about by depression 

 of the medullary respiratory centres and terminations of the 

 afferent vagi in the lungs. 



Temperature. — The bodily heat is reduced by aconite in 

 fever, after medicinal doses, and in poisoning by the drug. 

 Vascular dilatation, retarded circulation, and therefore heat 

 dissipation, probably explains the antipyretic action. 



Skin. — Aconite sometimes produces slight diarphoresis. 

 The cause of this action is unknown. 



