436 VEGETABLE DRUGS 



Extractum Aconiti. Extract of Aconite. (U. S. P.) 

 Made by maceration and percolation with alcohol, and evaporation 

 to pilular consistence. 



Dose.— H., gr.i. iii. (.06-.2); D., gr.J,.i (.006-.015). 



Extractum Aconiti. (B. P.) 

 Dosc—B.., gr.iii.-vi. (.2-.36); D., gr.ss.-i. (.03-.06). 



Fleming's Tincture. (Non-official.) (79 per cent.) 

 Dose—B,., Tilvii..xv. (.5-1.); D.. ni-ii. (.015-.12). 



ACONITE AND ACONITINE. 



Action External. — Aconite or aconitine applied to mucous 

 membranes, raw surfaces or the unbroken skin, irritates and 

 then paralyzes the nerves of touch and temperature. This 

 is evidenced in the human subject by a sensation of tingling 

 and burning, followed by numbness and local anaesthesia. 



Action Internal. — Digestive Tract. — Aconite in medicinal 

 doses has no special effect on the digestive organs. Toxic 

 doses produce nausea and retching, and, in animals capable 

 of the act, vomiting. 



Circukdiuri. — The chief therapeutic value of aconite 

 depends upon its influence over the heart and vessels. It 

 reduces both the force and frequency of the cardiac pulsa- 

 tions and lowers blood tension. The physiological details 

 accounting for this action are not positively known. It is 

 probable that the slowing of the heart is primarily due to 

 stimulation of the vagus endings in the heart, inhibitory 

 centre in the medulla, and cardiac motor ganglia; but 

 soon both the heart muscle and its contained ganglia are 

 progressively depressed, and, by lethal doses, paralyzed. 

 This local action of aconite on the heart is exhibited when 

 the drug is applied directly to the organ in situ, or to the 

 cut-out heart, when its 'pulsations are diminished in force 

 and frequency. 



The vasomotor system is only indirectly influenced by 

 depression of the sensory nerves, so that the normal peri- 

 pheral stimuli do not reflexly stimulate the vasomotor centre 

 and contract the arterioles. Therefore blood pressure is 



