The practical lessons, however, which all of you must lay to heart on this subject are: 1st. That you are in duty bound to acquire sound knowledge and great skill in your profession; since the consequences involved are of the greatest moment, your obligation is of a most serious nature. 2d. That in your future practice you will be obliged on all occasions to use all reasonable care for the benefit of your patients. 3d. That you cannot in conscience undertake the management of cases of unusual difficulty unless you possess the special knowledge required, or avail yourselves of the best counsel that can reasonably be obtained. 5. A second principle of Ethics in medical practice, gentlemen, is this, that many human acts may be highly criminal of which, however, human laws and courts take no notice whatsoever. In this matter I am not finding fault with human legislation. The laws of the land, considering the end and the nature of civil government, need take no cognizance of any but overt acts; a man's heart may be a very cesspool of vice, envy, malice, impurity, pride, hatred, etc., yet human law does not and ought not to punish him for this, as long as his actions do not disturb the public peace nor trench upon the happiness of his neighbor. Even his open outward acts which injure only himself, such as gluttony, blasphemy, impiety, private drunkenness, self-abuse, even seduction and fornication, are not usually legislated against or punished in our courts. Does it follow that they are innocent acts and lawful before God? No man in his right senses will say so. The goodness and the evil of human acts is not dependent on human legislation alone; in many cases the moral good or evil is so intrinsic to the very nature of the acts that God Himself could not change the radical difference between them. Thus justice, obedience to lawful authority, gratitude to benefactors, are essentially good; while injustice, disobedience, and ingratitude are essentially evil. Our reason informs us of this difference; and our reason is nothing else than our very nature as intelligent beings capable of knowing truth. The voice of our reason or conscience is the voice of God Himself, who speaks through the rational nature that He has made. Through our reason God not only tells us of the difference between good and evil acts, but He also commands us to do good and avoid evil;--to do certain acts because they are proper, right, orderly, suitable to the end for which we are created; and to avoid other acts because they are improper, wrong, disorderly, unsuitable to the end of our existence. There is a third class of acts, which, in themselves, are indifferent, i.e., neither good nor evil, neither necessary for our end nor interfering with its attainment. These we are free to do or to omit as we prefer; but even these become good and even obligatory when they are commanded by proper authority, and they become evil when forbidden. In themselves, they are indifferent acts.