490 Pharmacology of Indacomtine and Bikhaconitine. 
Summary. 
The two aconitines, indaconitine and bikhaconitine, agree in their qualita- 
tive effects with the other alkaloids of this series, aconitine, japaconitine, and 
pseudaconitine, which have been dealt with in our previous papers. 
The toxicity of indaconitine is less than that of bikhaconitine towards 
warm-blooded animals; in this respect the former stands very near to the 
aconitine of A. napellus, whilst the latter being somewhat stronger than 
japaconitine, is to be referred to a position between this alkaloid and pseud- 
aconitine from forms of A. ferox which is much the most active of the series. 
The depression of the respiratory function by indaconitine is less than that 
produced by bikhaconitine, and to this the greater toxicity of the latter is 
referable. Repeated doses of alkaloids administered at regular intervals and 
in similar fractional proportions of the lethal dose—are followed by a more 
marked toxic effect when bikhaconitine is administered rather than indaconi- 
tine. Towards frogs the toxicity of the two alkaloids under discussion is 
practically equal, bikhaconitine is more active than indaconitine in reducing 
the respiratory activity. On the other hand, it is somewhat less active in 
abolishing the excitability of muscular and intramuscular motor nervous tissue 
(immersion experiments), and in reducing the ability of the muscle-nerve 
preparation poisoned 7 situ for the performance of work sufficient to cause 
fatigue. The local effect of the two aconitines when applied to the skin by 
inunction, is equal and similar to that of the aconitines already considered. 
Indaconitine and bikhaconitine may therefore be substituted for aconitine 
and pseudaconitine for internal use, indaconitine being administrable in the 
same dose as aconitine (from A. napellus) and bikhaconitine in proportion of 
0°75 of the unit dose of the former, whilst for local application they may be 
used as contituents of ointments in similar proportions to aconitine. 
Pseudaconine from Pseudacomtine and Bikhaconitine. 
The action of these is, towards frogs, identical. Their toxicity appears to 
be practically equal and their effect generally similar to that of aconine (from 
aconitine). Their action is in the main curari-like in character. 
In conclusion it is an agreeable duty to add that many of the observations 
on temperature, together with control experiments upon the physiological 
action of the alkaloids discussed in this paper were accurately carried out by 
Dr. Croll, Second Assistant in the Materia Medica Department of Aberdeen 
University, whilst the specimens of the pure alkaloidal salts required in the 
experiments have been prepared in the laboratories of the Imperial Institute 
by Mr. A. E. Andrews, Salters’ Company’s Research Fellow. 

