240 VEGETABLE POISONS. 



probable by this circumstance; that some poisons which are very 

 powerful when applied to wounds even in small quantities, are 

 either altogether inefficient when taken internally, or require to be 

 given in very large quantities, in order to produce their effect, and 

 vice versa. 



A poison applied to a wounded surface may be supposed to act 

 on the brain in one of three ways. 



1. By means of the nerves, like poisons taken internally. 



2. By passing into the circulation through the absorbent vessels. 



3. By passing directly into the circulation through the divided 

 veins. 



Exp. 25. In order to ascertain whether the woorara acts 

 through the medium of the nerves, I exposed the axilla of a rabbit, 

 and divided the spinal nerves supplying the upper extremity, just 

 before they unite to form the axillary plexus. The operation was 

 performed with the greatest care. I not only divided every nervous 

 filament, however small, which I could detect, but every portion of 

 cellular membrane in the axilla, so that the artery and vein were left 

 entirely insulated. I then made two wounds in the fore-arm, and 

 inserted into them some of the woorara formed into a paste. Four- 

 teen minutes after the poison Was applied, the hind legs became 

 paralytic, and in ten minutes more he died, with symptoms precisely 

 similar to those which took place in the former experiments, and 

 the heart continued to act after apparent death. On dissection, the 

 nerves of the upper extremity were particularly examined, but not 

 the smallest filament could be found undivided. 



I made the following experiment, to ascertain whether the 

 woorara passes into the circulation through the absorbent vessels. 



Exp. 26. I tied a ligature round the thoracic duct of a dog, 

 just before it perforates the angle of the left subclavian and jugular 

 veins. I then made two wounds in the left hind leg, and introduced 

 some of the woorara in powder into them. In less than a quarter 

 of an hour he became affected with the usual symptoms, and died 

 in a few minutes afterwards. 



After death, I dissected the thoracic duct with great care. I 

 found it to have been perfectly secured by the ligature. It was 

 very much distended with chyle ; and about two inches below its 

 termination its coats had given way, and chyle was extra vasated into 



