142 Royal Society ;— 



with Antiar are simply dependent on the paralysis of the heart caused 

 by it. With reference to the irritabihty of the muscles and nerves, 

 on the contrary, it is easy to show that the ligature or excision of the 

 heart has not the same influence as the Antiar ; inasmuch as in the 

 first case the muscles and nerves are found irritable six or seven 

 hours, and more, after the experiment has been- made. Therefore it 

 may be said that the Antiar has a direct action on these organs. 



These points once demonstrated, there remained one more question 

 to elucidate, namely, whether the Antiar acts only upon the mus- 

 cles, or also upon the nerves. If we consider that the Antiar un- 

 doubtedly paralyses the muscles, we may easily see that the loss of the 

 excitability of the nerves possibly depends merely upon the impair- 

 ment of the muscular contractility, and is therefore not real, but only 

 apparent. With a view to determine the real state of things, I 

 tried a third series of experiments — poisoning frogs in such a 

 manner that the muscles of one limb were kept free from the influ- 

 ence of the poison. This was done in two ways : first, by putting 

 a ligature round the crural artery and vein of one leg ; and secondly, 

 bv cutting through a leg entirely, after the ligature of its vessels, with 

 the exception only of the ischiadic nerve. In poisoning frogs treated 

 in one of these ways, through a wound of the back, I found that, with 

 the exception of the heart, the Antiar acts in the first instance upon 

 the muscles. This is shown by the fact, that in the second hour, at 

 the time when the muscles of the poisoned parts have lost their 

 irritability, the nerves of the sacral plexus in the abdomen still 

 possess their full influence upon the muscles of the leg which has 

 been kept free from the action of the poison. One might be in- 

 clined from this to conclude, that the nerves are not at all acted 

 npon by the Antiar ; but this inference would be erroneous. In fact, 

 the experiments just mentioned, if followed a little longer, show 

 that in the third or fourth hour the sacral plexus also becomes 

 inactive, at a time when the muscles of the non-poisoned leg are 

 fully contractile. The Antiar, therefore, paralyses also the nervous 

 trunks, but later than the muscles. 



From all these experiments, it seems to follow that the Antiar is 

 a poison which acts principally npon the muscular system (the 

 heart and the voluntary muscles), a conclusion, in favour of which 

 I may further add, that the muscles and the heart of frogs poisoned by 

 Urari (Woorara, Curare) lose their irritability totally, and in a short 

 time, if Antiar is introduced into a wound some time after the Urari. 

 If we consider that, as I have shown (see Proceedings of the Royal 

 Society, 18 j6, p. 201), the Urari only acts upon the terminations of 

 the nerves in the muscles, and does not affect the irritability of the 

 heart and muscles at all, we may conclude, that a poison, which, 

 as the Antiar, is capable of paralyshig the muscles after the Urari, 

 has really a direct action upon the muscular fibre. 



The results of my investigation into the effects of the Antiar upon 

 frogs, are therefore the following : — 



1. The Antiar is a paralysing poison. 



2. It acts in the first instance and with great rapidity (in 5 to 

 10 minutes) upon the heart, and stops its action. 



