is produced by certain ve^eialle Poisons. 177 



After death, I dissected the thoracic duct wiih great care* 

 1 found it to have been perfectly secured by the ligature* 

 It was very much distended with ch\!e; and about two 

 inches beloW its termination its coats had given way, and 

 chyle was extravasated into the cellular membrane. The 

 lymphatic vessels ui the left axilla were distended in a very 

 remarkable deorce; and on dividing them, not less than a 

 drachm of Kmph issued from the divided ends. 



Since neither the division of the nerves nor the obstruc- 

 tion of the thoracic duct intcifere in the shghtest degree 

 with the eflbcts of the woi/iaia, there is pre.uunptive evi- 

 dence that it acts on the brain by csitering the circulation 

 through the divided veins. I endeavoured to ascertain, by 

 experiment, whether this is really he case. 



To apply ligatures to the lari;e vessels of a limb only 

 would evidently lead to no satisfactory conclusion, since the 

 anastomosing vessels might still carry on the circulation* 

 The only way which 1 could devise of performing the ex- 

 periment, was to include all the vessels, sniall as well a3 

 large, in a ligature. 



£lxp. 27. In order to make the experiment more satis- 

 factorily, I exposed the sciatic nerve of a rabbit in the uppef 

 and posterior part of the thigh, and passed under it a tape 

 half an inch wide. I then made a wound in the leg, and 

 having introduced into it some of the woorara mixed with 

 water, I tied the tape moderately tight on the fore-part of 

 the thigh. Thus I mlerrupted the communication between 

 the wounds and the other parts of the bodv, by means of 

 the vessels, while that by means of the nerve still remained. 

 After the ligature was tigliiened, I applied the woorara a 

 second time, in another part ot the kg. The rabbit was 

 not at all afiected, and at the end of an hour ] removed the 

 ligature. Being engaged in some other pursuit, I did not 

 watch the animal so closely as I should otherwise have done; 

 but twenty minutes after the ligature was removed, I found 

 hin) lying on one side, motionless and insensible, evidently 

 under the influence of the ))()ison ; but the symptoms were 

 less violent than in most instances, and after lying in this 

 stale he recovered, and the limb became perfectly warm, 

 and he regained the power of using it. 



Exp. 28. I repeated the last experirnent with this differ- 

 ence, that after having applied the poison, I m.Tde the liga- 

 ture as tight as I could draw it. 1 renu)ved the ligature at 

 the end of an hour and twenty minutes, but the animal waa 

 not at all affected either before or after the removal of the 

 Vol. 38. No. 161. Sept. 1811. M ligature, 



