OF THE CALABAR BEAN. 777 



When applied to Striped and to Unstfjped Muscle. 



Although physostigma, when acting through the blood, does not destroy 

 muscular contractility, the contact of a concentrated preparation is immediately 

 followed by very rapid paralysis of the portion of muscle to which it is applied. 



Experiment XCVI. 



The two gastrocnemii muscles of a frog, and portions of the sciatic nerves in the thighs, 

 were exposed and separated from contiguous structures. The muscles were completely isolated 

 by pieces of parchment. A pad soaked in a concentrated mixture of extract and water, was 

 placed on the surface of the right muscle, and a similar pad moistened with water, was placed 

 on the left : the muscles being at the time completely under the control of their sciatic nerves, 

 and being readily excited to contractions by direct galvanism. 



Four minutes afterwards, a weak galvanic current was applied to the left nerve, and produced 

 energetic contraction of all the muscles supplied by the nerve ; and the left gastrocnemius muscle 

 also contracted forcibly when directly stimulated. The same current was then applied to the 

 right nerve, and caused pretty active movements of the right leg ; in which, however, the gas- 

 trocnemius only sluggishly participated. 



In fifteen minutes, the right or poisoned gastrocnemius was perfectly paralysed; while the 

 left muscle appeared to be as active functionally as vjhen the experiment was commenced. 



The pad soaked in the extract was then removed from the right muscle and placed on the 

 left. In five minutes, the contractility of the latter was considerably impaired ; and in twenty 

 minutes, no contraction could be produced, even when it was stimulated by very strong galvanism. 



It was found that when a portion of intestine in energetic peristalsis, had its 

 surface painted over with a concentrated watery mixture of the extract, it be- 

 came flaccid ; and that when a vermicular contraction ran along towards this 

 portion, it stopped at the margin of the portion, and appeared to skip over it, as 

 the peristalsis was resumed at the nearest unpoisoned point of the intestine. 

 Soon afterwards, the poisoned portion of intestine could not be stimulated to 

 contract by strong galvanism. 



When applied to the Heart. 



For the purpose of examining the topical effects on the heart, frogs were 

 generally employed, but warm-blooded animals were in a few instances made 

 use of. 



The conditions of the experiments were varied by the application of the poison 

 to the visceral pericardium, and to the muscular substance of the heart ; with- 

 out, and after, its removal from the body ; and by the insertion of the poison into 

 one of the cardiac chambers. 



1. Without its Removal from the Body. 



a. To the Visceral Pericardium. 



Experiment XCVII. 

 The exposed heart of a frog was found, during ten minutes, to have an average rate of 

 seventy beats in the minute. 



