It would be difficult for four more interesting or important questions for the practical and scientific surgeon than these. But in proportion to their importance are the difficulties which surround them. These, however, are grappled with by the author courageously, patiently, and honestly, and the result is at all events a series of experiments of extreme interest, whatever be the conclusion, we may feel disposed to draw from them. Indeed, the writer himself seems to have set out upon his investigation purely with the desire to learn whatever is to be learned on the points stated, by careful and patient anatomical research, and without being wedded to any particular theory in regard to them, or desiring to force any conclusion. Recognizing the great importance of the subject, and the efforts that have been made by others in the same direction to throw light upon it, notably by William, Ponfick, Orth, Bellien, Zuelzer, and Lukomsky, he has recognized many points in which these observers have failed, and has endeavored, in following out somewhat similar lines of research, to avoid their, and other, errors. To the danger of one great source of possible error the author seems specially alive, the introduction of other matters into the system of the animal operated on than the mere morbid fluid inoculated, and this he has endeavored to guard against by the most scrupulous cleanliness in obtaining, preparing and introducing such fluids into the bodies of animals. In touching upon the first question his first case is to define as clearly as possible what are the clinical features which characterize erysipelas in the human subject. He then details in all his experiments, and, from the kind of success of five out of twenty-five inoculations he believes there can be no doubt “that erysipelas is inoculable in rare cases; that fluids from an erysipelatous part, display a specific contagious action.” In three cases he inoculated animals from the human subject successfully with erysipelas, and in two cases animals were infected from other animals. He believes, too, that one human subject might be inoculated from another. In regard to the second question propounded, four experiments were made with erysipelatous inoculation material, which had been potent in other cases, but here a portion of 2–4 per cent. solution of carbolic acid was added. In none of these cases was there any appearance of either local or general symptoms of any disease. In answer to question III, all the author’s results were negative. In no case was erysipelas produced by even the most putrid inoculations, when they were not taken from an erysipelatous part. In several cases, however, the animals died of distinct septicæmia.