first, tincture of rhubarb was given, to the quantity of a pint and a half in three doses of half a pint each, with the same quantity of water. The fourth and fifth had powdered rhubarb made into a bolus, and the sixth took three pints of infusion of rhubarb.
When the asses were killed, equal quantities of blood were taken from the splenic vein and from the left auricle of the heart, or from the vena cava, and suffered to coagulate, that the serum of each might be obtained for examination by alkalies, in comparison with each other, and with the urine of the animal, as well as with infusions of its spleen and of its liver in water.
In the first of the experiments with tincture of rhubarb, the infusion of the spleen had a tint of colour equal in intensity to that of sixty drops of tincture of rhubarb in two ounces of water; the serum from the blood of the splenic vein, to fifteen drops; the serum from the auricle, to three drops. The urine had so deep a tinge that it nearly resembled the pure tincture itself.
In the second and third experiments the results were nearly similar, but less intense. But in those asses to which the rhubarb boluses had been given without any fluid, the spleen was found in its contracted state, with cells scarcely visible, and without sensible impregnation by the rhubarb; but the caecum and colon contained several quarts of fluid, in which the rhubarb was more evident both to sight and smell than in the stomach. The urine also was highly impregnated with the colour of the rhubarb. The effects from infusion of rhubarb were perfectly similar to those from the tincture, but the colours occasioned by it were not so intense.
In the course of these experiments, an attempt was made to ascertain whether the blood from the splenic vein contained more serum than that from other parts of the body; but the difference observable was not so great as it was afterwards found might be occasioned by other circumstances.
From the experiments contained in his former and present paper, Mr. Home considers it ascertained that the spleen is sometimes found distended to double the bulk which it occupies in its more contracted state.
In the distended state there is a cellular structure distinctly visible, but in the contracted state these cells cannot be seen without a magnifying-glass; the difference between these states depending upon the quantity of liquid that was contained in the stomach before death.
If the fluids contained in the stomach be coloured with tincture of rhubarb, the spleen and the blood in the splenic vein are coloured also, more strongly than the liver or blood contained in other veins of the body; so that the colour cannot arrive at the spleen through the ordinary course of the circulation. But when the stomach is kept without liquids, although the colouring matter be carried through the system to the urine by the ordinary channel, no particular evidence of it is to be met. with in the spleen or its vessels; but the principal absorption takes place from the czecum and colon. No vessels, however, have been discovered by which the communica-
