An Extract of a Letter, Relating an Experiment Made for Altering the Colour of the Chyle in the Lacteal Veins, by Martin Lister Esq

The Profile and Ground-Plot of the Concave in Pen Park, before described. A The Superficies of the Earth. B The old Lead-Oar Pit. C The Tunnel or Passage down. D The long Gallery. E The Concave or Cell. F The upper edge of the Mud. G Two Small Rocks that appear above the water. H The upper part of the Water. I The bottom of the water. K The highest mark of the water. L Two Rocks. An Extract of a Letter, relating an Experiment made for altering the Colour of the Chyle in the Lacteal Veins, by Martin Lister Esq. The passage of the Chyle through the Intestines into the Lacteal Veins, is a thing hitherto demonstrated to the Eye by none. Dr. Lower ingeniously confesseth the ill success he had in trying with Aer, or with ringed Spirit of Wine; by neither of which he was able to force a passage. And J. Walaeus (Epist.de motu Chylis) is very positive, that however the Chyle in the Intestines may be diversly coloured; yet it is still white in the Lacteal Veins. And Diermerbrock in his late Anatomy Published 1672. (p. 37.) affirms, Chylum semper album inveniri in Vas Lacteis Aferenteriis & Thoracicis—vividem vero rubrum alteriusve coloris, in his a nemine habere visum fuisse. Notwithstanding which, and my own former unsuccessful Tryals (Phil. Trans. Numb.95.) I did not doubt but that some happy Experiment would shew the contrary; and a purposely coloured Chyle might find admittance into the Lacteal Veins though not by force, yet by the Consent and Introduction of Nature herself. The success of some late Experiments I made to this purpose, I shall here acquaint you with. Ex- Experiment I. I caused a Dog to be fed, and after four hours, or thereabout; and having ready by me a clear Tincture of Indigo, dissolved in fair Water and filtered, I opened the Abdomen, and making a small Incision in the Jejunum, I injected an ounce or two. This done, we stitch'd up the Gut, and all, again, and the Dog turned upon his Legs. After one hour and a quarter, we cut the stitches; and then beheld a copious Distribution of Chyle and turgid Lacteal Veins; but as white as ever. And yet carefully searching the Guts, we perceived none of the Injected Liquor anywhere. Exper. II. Another Dog, which was kept fasting 40 hours, had a very little flesh, without water, given him, about 5 hours before the Injection of the Tincture of Indigo; which was performed after the same manner, as before: only it was now well warmed, and about Twelve Ounces thrown up the Duodenum, and down the Ileum. Here were empty Guts, and not the least appearance of any Lacteal Veins in the Mesentery. After full 3 hours, the Stitches were cut again (some business hindring me from doing of it sooner) and carefully examining the Mesentery, we found many Lacteal Veins of an Azure Colour; and cutting some of the biggest of them asunder, we plainly saw a thick blewish Chyle to issue forth, and to spread itself over the transparent Membranes of the Mesentery. This is a very truth, which the Chirurgeon I employed to assist me, in the Experiment, can well witness, whose Eyes I used, as well as my own, in carefully examining these matters. Whence, although it hath been doubted of by some, yet is it most evident, That the Lacteal Veins receive, what they carry, from within the Cavity of the Intestines.