mere reaction_; that it has its roots far down in the history of science. The first mention of it in the book, however, is made for the purpose of disavowing the claim, advanced by many homoeopathists, to Hippocrates as one of their order. Not to mention the curious story about Galen and the patient ill from an overdose of theriacum, who was cured by another dose of the same substance, nor the ridicule of the doctrine of contraries by Paracelsus and Van Helmont, nor the fact that the _contraries_ of Boerhaave, by his own explanation, merely signify whatever substances prove their contrariety to the disease by curing it--to pass by these, we find one of the main objects of homoeopathy, the discovery of specifics, insisted upon by Lord Bacon in his words already quoted. Not that homoeopaths, while they depend upon specifics, believe that there is any such thing as a specific for a disease--a disease being as various as the individuality of the human beings whom it may attack; but that an approximate specific may be found for every well-defined stage in every individual disease; a disease having its process of change, development, and decline, like a vegetable or animal life. Besides an equally strong desire for specifics, and a determined opposition to compound medicines, Boyle, who was born the year of Bacon’s death, and inherited the mantle of the great philosopher, manifests a strong belief in the power of the infinitesimal dose. Neither Bacon nor Boyle, however, were medical men by profession. But Sydenham followed them, according to Dr. Russell, in their tendency towards specifics. It is almost needless to mention Jenner’s victory over the small-pox as, in the eyes of the homoeopaths, a grand step in the development of their system. It gives Dr. Russell an opportunity of showing in a strong instance that the best discoveries for delivering mankind from those ills even of which they are most sensible have been received with derision, with more than bare unbelief. This is one of his objects in the book, and while it is no proof whatever of the truth of homoepathy, it shows at least that the opposition manifested to it is no proof of its falsehood. This is enough; for it seeks to be tried on its own merits; and its foes are bound to accord it this when it is advocated in such an honest and dignified manner as in the book before us. The need of man, in physics as well as in higher things, is the guide to truth. With evils of any sort we need no further acquaintance than may be gained in the endeavour to combat them. The discovery of what will cure diseases seems the only natural mode of rising by generalization to the discovery of the laws of cure and the nature of disease. Those portions of the volume which discuss the influence of Christianity on the healing art, likewise those relating to the different feelings with which at different times in different countries physicians have been regarded, are especially interesting.