ABSORPTION BY BLOOD-VESSELS. 419 



with the game result. In other experiments, the leg was sep- 

 arated from an animal, all the parts being divided except the 

 crural artery and vein ; and in one experiment, a quill was 

 introduced into each of these vessels, secured with ligatures, 

 and the vessels themselves divided, so that there could be no 

 communication of the leg with the body except through the 

 circulating blood. Under these conditions, the poison intro- 

 duced into the foot produced its effects upon the system in 

 ordinary time ; while it was found that the effects of the 

 poison could be retarded or arrested by simple compression 

 of the vein. These experiments, which are models of inge- 

 nuity and accuracy, removed all doubt of the fact that ab- 

 sorption takes place by blood-vessels. 



Most of the experiments which followed those of Magen- 

 die simply confirmed his results. Tiedemann and Gmelin, as 

 the result of a very elaborate series of investigations, showed 

 that alimentary matters, odorous and coloring matters, and 

 various saline and metallic substances, when taken into the 

 alimentary canal, find their way into the system by the ab- 

 sorbents and the thoracic duct, and by the radicles of the por- 

 tal vein. 1 Finally, Segalas, in 1822, supplied about the only 

 link wanting in the chain of evidence developed by the origi- 

 nal experiments of Magendie. He demonstrated that poi- 

 soning did not follow the introduction of a solution of nux 

 vomica into a loop of intestine separated from the rest of the 

 canal, so long as the circulation was interrupted, or when the 

 blood returning from the part by the vein was discharged 

 from the vessel and not carried into the general circulation. 2 



At this time the subject of vascular absorption attracted 

 a great deal of attention among experimental physiologists ; 

 and a committee, consisting of Drs. Harlan, Lawrence, and 



1 TIEDEMANN ET GMELIN, JRecherches sur la Route qui prennent diverses Sub- 

 stances pour passer de VEstomac et du Canal Intestinal dans le Sang ; sur la 

 Fonction de la Rate et sur Us Voies cachees de V Urine, Trad, par S. Heller, Paris, 

 1821. 



2 SEGALAS, Note sur F Absorption Intestinale. Journal de Physiologic, Paris, 

 1822, tome ii., p. 117 ft scq. 



