The Pharmacology of Pscudaconitinc and Japaconitine. 381 



be seen in each, and the substitution of a veratryl group (in pseud- 

 aconitine) for an acetyl group (in aconitine) counts for little in 

 influencing the characteristic physiological action. 



In order to bring the action of aconitine, pseuclaconitine, and 

 japaconitine into a contrast, which may be readily apprehended at 

 a glance, the following summary will be useful. 



Heart. — All three alkaloids have a similar effect upon the heart of 

 such mammals as have been observed. Pseudaconitine is quantita- 

 tively more energetic than the other two, towards cats, but is certainly 

 not nearly twice as toxic when artificial respiration is practised. 

 Towards the frog's heart pseuclaconitine is slightly less powerful than 

 the other two, of which japaconitine is rather the more active. 



Vagus Nerve and Inhibitory Mechanism in Heart. — Heart slowing from 

 increased central vagus activity is produced by all these alkaloids, and 

 similar results follow section and stimulation of the nerve at this and 

 later stages of poisoning by one and all of them, both in mammals and 

 frogs. 



Respiration. — There is less tendency to acceleration of respiration in 

 mammals poisoned by pseudaconitine than when the other two alka- 

 loids are employed ; further, the dyspnceal conditions develop more 

 suddenly and the central depression of respiration is greater. Jap- 

 aconitine is at first slightly more depressant than aconitine, but 

 thereafter the tendency to acceleration of respiration is sooner 

 developed, otherwise the general features of their action are similar. 



Blood. — All the aconitines produce a deleterious effect upon the 

 haemoglobin and coloured corpuscles of the blood when they are given 

 repeatedly in large doses. As far as has been ascertained this is due 

 to impairment in the nutrition of the animal rather than to a direct 

 action. 



Frogs kept in a watery medium or in contact with a moist surface 

 develop cedema after receiving any of the aconitines, but this condition 

 is most marked and the hydremia of the blood is more pronounced 

 and lasting after pseudaconitine. 



Brain and Cord. — All aconitines appear to have a similar effect 

 qualitatively on the brain and cord of rabbits, pigeons, and frogs. 



Temperature. — The initial elevation of temperature often seen in 

 rabbits which have received aconitine or japaconitine is less frequently 

 observed after pseudaconitine. A slightly greater and more enduring 

 fall of internal temperature is witnessed after the latter, when the dose 

 is large and bears a like relationship to the lethal amount. 



Repeated Administration. — Some tolerance is established on the part 

 of rabbits towards all the aconitines, and this is manifested with 

 reference to temperature reduction, to the cardiac effect, and, to a 

 lesser extent, to respiration ; the general toxicity undergoing a 

 reduction which is not, however, extensive. Less tolerance is shown 



