When first discovered, and the office assigned to them could no longer be disputed, the general distribution of them was still doubted. As it was usual to render them visible by filling them with quicksilver, so, with a kind of reasoning which has too often characterized mere anatomical research, when they could not be made visible, it became the fashion to doubt their existence. Amongst other structures, Bone was formerly one in regard to which people found a difficulty. How could such delicate vessels exist in such an apparently dense structure? But Mr. Abernethy, who, like Bacon, had always opposed mere eye-reasoning, used to observe, with equal simplicity and good sense, that, for his part, he could see no more difficulty in an absorbent taking up a particle of bone, than he could in comprehending how a vessel could lay it down, which nobody doubted. We now know that bone is not only supplied with all the vessels which characterize a living structure, but so liberally, that, in comparison with some other structures of the body, we regard it as a part of high organization. Nevertheless, the extreme minuteness and transparency of these absorbent vessels naturally led persons to regard with considerable interest any magnified view of them, such as that afforded by larger animals. In the paper before us, which was published in the "Philosophical Transactions" for 1793, Mr. Abernethy gives the account of his examination of the absorbents in a whale; and his object was to help to determine a question long agitated, whether the glands or kernels were composed of cells, or whether they were merely multiplied convolutions of vessels. He selected the absorbents from the situation to which I have already referred. He threw into the arteries which carry blood to nourish the gland, a red solution containing wax, which of course became solid on cooling; and into the veins which return the blood from all parts, a similar solution, only coloured yellow. He filled the absorbents with quicksilver.