102. In proof of the accuracy of the second position, we have equally strong evidence founded on experiments. Magendie introduced camphor into the veins of a pregnant bitch, and he found that the blood of the fœtus had, at the expiration of a quarter of an hour, acquired distinctly the smell of that drug (Physiology, 2d Edit. 1825). Quadrupeds carrying young were made to take with their food four ounces of madder-root. The colouring matter of that substance was found to have passed from the mother to the fœtus; as all the serum of the blood of the latter, the urine, the liquor amnii, the teeth and the bones were tinged with it (Dr. Mussy, 1829)[25]. In 1827, I undertook, at the request of Sir E. Home, a set of experiments on the human subject, with a view to ascertain the truth of my second position. Six gravid patients of one of the lying-in institutions under my direction, who required the constant use of aperient medicines, were instructed, towards the close of their time of gestation, to take at night, for a period which averaged about a week, from ten to fifteen grains of rhubarb in powder. After two or three days the effect was visible in the colour and smell of the urine of the patients previous to their confinement, and in one of them, in the colour and smell of the transpiration also. During the labour care was taken to preserve part of the amnionic fluid in a cup, the umbilical vessels were suffered to bleed on the side of the child after their recision, and the blood set apart so as to separate the serum, which was obtained in small quantity only.—Lastly, the first urine of the child was collected in sufficient portions. Each of these secretions appeared distinctly tinged by the yellow root, and bore the smell of it. When carbonate of magnesia was mixed with the fluids their colour became lateritious, and a reddish sediment was thrown down, evincing the presence of the drug which the mother had ingested. (MS. notes.) ERRATA. PROLEGOMENA.— Page iii, Prop. 20, _for reference_ (16), _read_ (17). Page vii, Prop. 39, _for_ Haygton, _read_ Haighton. ———— idem, _for_ Embryoni, _read_ Embryonis. Page viii, Prop. 46, 1st line, _dele_ (5). PLATE III.— Page 9, Exp. of Fig. 13, _for_ membrane proper, _read_ membrana propria, and the same mistake occurs at pages 11, 14, and 26. The following letter from the artist to whose skill and patience I am indebted for the principal part of the engravings, and the entire colouring of the present collection, is inserted in this place, with the hope of increasing that confidence in the reader, with which it is desirable that graphic representations of extraordinary or anomalous objects should be received. 9, Warren Street, Fitzroy Square, January 27, 1832. DEAR SIR,