And first, of the second question. Not to speak of the many authors on matters of this description, who preceded Dr. Hunter and Professor Soemmering, in giving representations of the human embryo in many of its metamorphoses, such as Ruysch, Noortwyk, Albinus, Krapft, Wrisberg, Camper, Blumenbach, Denman, and others, I am ready to admit that both Hunter and Soemmering had given to the world delineations, such as are here referred to, which ought to satisfy the medical profession. The one in his splendid work on the “Gravid Uterus”, gigantic folio edition—the other in his no less valuable folio plates of the human embryo. But, unfortunately, neither of those works can be considered as accessible to the generality of professional readers, on account of their high price and rarity; and even if either were accessible, the subjects therein treated are viewed differently from those collected in the present work. Those works, moreover, present no coloured specimen of delineations of parts, most of which, if not all, from that simple circumstance, lose their principal value;—and as productions of art they are not equal to what Mr. Perry has enabled me to offer to the public. Soemmering himself, in his “_Icones Embryonum Humanorum_”, admits, that although those who had gone before him in the same channel of inquiry, had produced valuable works and splendid plates, particularly Dr. Hunter and Dr. Denman; there was yet room for a more complete, and, above all, for a more minute representation of the metamorphoses of the human embryo. “_Elegans profecto et utilis admodum speculatio!_” exclaims the veteran physiologist; and forthwith he proceeds to compare what he had been able to give to the public on the subject of embryology with that which his predecessors had done. This leads him to the conclusion that, from having paid greater attention to minuteness, from being more strictly accurate, from the advantage of having a better collection of specimens than fall to the lot of most anatomists, and from the circumstance of both his delineator and engraver being much superior to those of former times—he had been able to complete a work of art on the progressive development of the human fœtus which left those of his predecessors far behind.