75 



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, 

 by 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 whlfch 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 

 upon 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 upon 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, 1856, 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 paralysing 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 : 



