fices on account of the material particles of which this fluid is composed ; the lymph they suppose enters the vessels by imbibition through their coats.
Before alluding to the other opinions on the subject of the origin of the lymphatic vessels, it may be as well to premise the changes which have taken place in our physiological notions with respect to the function of ab sorption since the time of the Hunters and their immediate successors. Magend'e has proved by numerous convincing experiments, that imbibition does take place in the living as well as in the dead body, not only through the coats of the lymphatics and bloodvessels, but through all the tissues. It has been equally well established by Magendie, Delille, Segalas, Blayer, Emmert, and other physiologists, that we can no longer exclude the veins from parti cipation in the important function of admitting new and foreign matters into the animal sys tem. With respect to imbibition, I will select one of many experiments instituted by Alagendie. lie exposed the external jugular vein in a dog, and having separated it from its cellular attachments, placed a piece of card underneath the vessel so as to isolate it from the surrounding parts. Ile now applied to the centre of the vein a watery solution of the spirituous extract of nux vomica. In four mi nutes the symptoms of poisoning made their appearance. If then it be admitted that imbibi tion takes place in the living textures, there can be no longer an absolute necessity for open mouths to the origins of the absorbing vessels, and it follows that the lymphatics cannot be the sole agents in the process of absorption.
I will now adduce some experiments con ducted by different physiologists, proving the en trance of varioussubstancesinto the living animal system by other channels than the lymphatics. Magendie divided all the structures of the hind leg of a living dog, with the exception of the femoral artery and vein, through which the circulation was carried on. He then inserted the upas tieute poison into the foot of the mutilated limb. The animal was poisoned in
the usual space of time required for this sub stance to take effect. Ile repeated the same experiment with the additional precaution of placing inert tubes into the artery and vein, and afterwards dividing these vessels, leaving the limb connected to the trunk by the tubes only, through which the blood passed to and from the limb ; the same effect followed on the introduction of the poison.
Mayer injected a solution of prussiate of pot ash into the lungs of an animal : in from two to five minutes after the injection, the serum of the blood, tested by a salt of iron, gave evidence of the presence of the prussiate of potash by the usual green or blue precipitate. It was detected in the blood long before it could be perceived in the contents of the tho racic duct, and in the left side of the heart be fore it appeared in the right. It was therefore evident that the pulmonary veins and not the lymphatics had first received the prussiate of potash and conveyed it to the heart. Scgalas included a piece of intestine between two liga tures in a living animal, and tied all the blood vessels leading to it excepting one artery ; the lacteals were left uninjured and pervious ; an aqueous solution of nux vomica was now in jected into the piece of intestine and there secured for an hour without producing any symptoms, but on removing the ligature from one of the veins, the poison took effect in six minutes. The converse of this experiment was performed by Magendie and Delille. A por tion of intestine of a living animal was in cluded between two ligatures ; the lacteals pro ceeding from it were ligatured and divided, the bloodvessels being left pervious. A so lution of nux vomica thrown into this piece of intestine destroyed the animal in six minutes. Emmert applied a ligature to the abdominal aorta in a dog, and afterwards inserted prussic acid into the foot of one of the hind legs; no ill effects followed in seventy hours; the liga ture was then removed, and in half an hour symptoms of poisoning appeared.