a 



071 the Organs of Absorption. 12g 



I have personally assisted M. Dupuytren in opening a 

 horse, the thoracic duct oF which he had tied more than 

 six weeks before, and I easily satisfied myself that there 

 existed evident cominnnications between the inferior por- 

 tion of the duct and the subclavian veins, although this 

 canal was entirelv destroyed at the place of the ligature. 



J now proceed to the experiments which 1 made, for 

 the most part in concert with M. Detile, to determine 

 whether the lymphatic vessels are really the only ones by 

 which foreign substances enter into the venous system. 



A circumstance that has always thrown some obscurity 

 over the experiments upon absorption, is the difficulty of 

 demonstrating, with certainty, the passage and preseiice of 

 absorbed matters, either in the lymphatic or sanguiferous 

 vessels. We have not these inconveniences to fear in em- 

 ploying the lipas, or the mix vomica^ for it is known that 

 two centigrammes of these substances produce effects too 

 remarkabfe to be mistaken. 



Would the ligature round the thoracic duct stop the 

 passage of the poison in the sanguiferous system, and con- 

 sequently its effects upon the spinal marrow ? This was 

 the first question that we proposed to resolve. 



I applied in a dog a ligature to the thoracic duct, a 

 little bei'ore its cpemng into the left subclavian vein; I 

 afterwards introduced a solution of the upas into the cavity 

 of the peritoneum. The effects of the poison were as 

 prompt and marked as if the thoracic canal had not been 

 tied. I have tried the same ligature in other animals ; but 

 instead of introducing the p(^isou into the cavity of the 

 peritoneum, I introduced it either into the pleura, or into 

 the stomach, the intestines, or n;uscles of the thighs, he. 

 The effects have always been equally rapid and intense, as 

 if the thoracic canal had been free. 



Decisive conclusions cannot be drawn from these first 

 essays, for we know that the thoracic canal is not the only 

 point of communication between the lymphatic and ve- 

 nous systems. There is ordinarily, on the right side, a 

 second thoracic duct, almost as considerable as that on the 

 left ; the large lymphatic vessels often open themselves so- 

 litarily into the subclavian veins ; and more frequently still 

 the lliotacic duct has several mouths into the veins where 

 it terminates. 



One of these circumstances was found to occur in the 

 animals subjected to our experiments -, and we must havB 

 recourse to other trials, from which other results, less equi- 

 vocal, may be deduced. 



Upon a dog who had eaten a large quantity of meat 

 Vol, 40, No . 1 72. August 1812. 1 seven 



