Diseases of the Heart.

In this edition Mackenzie has added much new material, and there has been a genuine revision and liberal rewriting. More emphasis is laid on the findings of the electrocardiograph, and there is more clearly brought out the relation of symptoms and signs to altered physiology. Therapeutic measures, as the use of digitalis in auricular fibrillation, are explained on scientific principles rather than on the ground of empiricism. The book is up to date, well written, and from the publishers' point of view of printing, illustration and binding, all that could be desired. An appendix of nearly one hundred pages contains instructive records of a large number of illustrative cases. No one familiar with the literature of diseases of the heart will question Mackenzie's right to speak with authority, especially on questions connected with pulse-tracings and the use of the polygraph. At the same time there is uttered once in a