372 POISONS : THEIR EFFECTS AND DETECTION. [§ 438. 
Insects. —The senior author has made experiments with the active 
principles of aconite upon blow-flies. An extract was made by allowing 
the ordinary tincture to evaporate spontaneously at the temperature of 
the atmosphere. If a minute dot of this is placed upon the head of a 
blow-fly, absorption of the active principle takes place in from fifteen to 
thirty minutes, and marked symptoms result. The symptoms consist 
essentially of muscular weakness, inability to fly, and to walk up per¬ 
pendicular surfaces ; there is also, in all cases, a curious entanglement 
of the legs, and very.often extrusion of the proboscis ; trembling of the 
legs and muscular twitchings are frequent. A progressive paralysis 
terminates in from four to five hours in death ; the death is generally 
so gradual that it is difficult to know when the event occurs, but in one 
case there were violent movements of the body, and sudden death. 
Fish. —The action on fish has been studied by Schulz and Praag. 
There is rapid loss of power and diminished breathing ; the respiration 
seems difficult, and the fish rapidly die. 
Reptiles : Frogs. —Plugge, in experiments on frogs, found no 
qualitative difference in the action of any of the commercial samples of 
aconitine. This fact gives the necessary value to all the old experiments, 
for we now know that, although they were performed with impure or 
weak preparations, yet there is no reason to believe that the symptoms 
described were due to any other but the alkaloid aconitine in varying 
degrees of purity or dilution. Frogs show very quickly signs of weak¬ 
ness in the muscular power ; the respiration invariably becomes laboured, 
and ceases after a few minutes ; the heart’s action becomes slowed, 
irregular, and then stops in diastole. The poisoned heart, while still 
pulsating, cannot be arrested either by electrical stimulation of the 
vagus or by irritation of the sinus, nor when once arrested can any 
further contraction be excited in it. Opening of the mouth and ap¬ 
parent efforts to vomit, Plugge observed both with Rana esculenta 
and Rana temporaria. He considers them almost invariable signs of 
aconitine poisoning. A separation of mucus from the surface of the 
body of the frog is also very constantly observed. Dilatation of the 
pupils is frequent, but not constant; there may be convulsions, both 
of a clonic and tonic character, before death, but fibrillar twitchings 
are seldom. 
Action of Aconitine on the Heart. 
Bohm 1 has made researches on the action of aconitine on the frog’s 
heart. After a subcutaneous injection of 5 mgrms. the heart beats 
quicker owing to stimulation of the motor ganglion ; then, as the motor 
ganglion begins to be paralysed and simultaneously the brake-apparatus 
( Hemmuncjs-vorrichtungen) stimulated, the beats are slowed and 
1 Studien iiber Herzgifte. 
