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possible. The upper end of the tube had been drawn out with the blow-pipe to much smaller size and a short piece of indiarubber tubing adapted, so as to admit of clamping with catch-forceps. When blood appeared at the end of the caoutchouc tube the clamp was applied. The whole apparatus was then rapidly inverted and the piece of vein removed, leaving the blood in a vessel of ordinary solid matter without any contact of living tissue. The glass tube was steadily clamped to a retort stand, and its orifice covered with a loose cap of guttapercha tissue to exclude dust, after which all was left undisturbed for 24 hours. On then turning out the blood, I found it all fluid except a layer of clot about one-eighth of an inch in thickness, which encrusted the interior of the tube, and also a little clot at the surface, which might be explained by some drying on account of the imperfect fitting of the cap. The fluid part of the blood soon coagulated.
The result of this experiment seemed to me of itself sufficient evidence that the blood requires no action of the living vessels to maintain its fluidity, and that the hypothesis of such action was superfluous.
At the same time the extreme care required in order to ensure the success of such an experiment indicated the subtilty of the influence of an ordinary solid in bringing about coagulation. A very simple experiment, performed in a butchers establishment on the way from my fathers house at Upton to
