In this book is discussed the morality involved in the ordinary cases of medical homicide and mutilation. Craniotomy has been omitted because this operation on the living child is never morally licit, and when done on the dead fetus it has no moral quality that requires explanation. The articles may seem to be intended for Catholic physicians and spiritual directors alone, but the desire in writing them was to reach all practitioners, to the end that the Natural Law which binds every man may be observed. Morality is not made such in its fundamental principles by any religious creed, but by the requirements of Divine Order, which finally prevails no matter what the opposition. Killing and maiming without sufficient extenuation did not become unlawful solely by the establishment of Christianity. Practically, however, physicians who have no religion, or a religion which is so illogical as to pay no attention to dogma, or even to rail at it as obtrusive, necessarily gravitates to the emotional in morality, and the principles of this book will not even interest them. Dogmas are abstract propositions, and all human society rests on abstract propositions. The most vital facts in morality, the basic distinction between crime and all that is virtuous or indifferent morally, is in abstract principle alone, but physicians and pastors who are not trained in philosophy and rational religion cannot appreciate an abstract principle--they are influenced only by the concrete. Obstetrical text-books, unfortunately, are written by such emotional men; by men who lack all training in ethics other than that inculcated in childhood out of the mental vagaries of the women in the household; and these authors prescribe therapeutic homicide as if it were a drug in the American Pharmacopœia. The reader is told that if the patient is a Catholic he is to respect her religious "prejudices"; if she is not a Catholic one need not bother about moral scruples when it is necessary to take a life to stop fits. Since the civil law does not prosecute a physician for therapeutic abortion on an inviable child, most physicians deem such an act not only permissible but scientific, and they hold that if a man's conscience will not let him kill a fetus to alleviate maternal distress he is guilty of malpractice.