In all legislation which endeavours to protect and improve national health the medical profession is necessarily consulted. The advice of experts is indispensable in framing measures which affect such important subjects as wholesome food-supply, the healthy housing of a people, the prevention and spread of epidemic diseases, etc. Indeed, so important is the connection of a sound body with a sound mind, and so linked together are all classes of society, that common-sense and rational foresight will more and more recognise that health regulations are a subject of national concern as well as of individual instruction, and the advice of the medical profession will be increasingly needed. It is, however, equally certain that with the advance of intelligence, of education, and of political power amongst all members of a community, the great principle of Justice must become the foundation on which all legislation, which is to prove of permanent benefit to a nation, will rest. Expediency, regardless of justice, may sometimes seem to offer an easy solution of difficult practical problems, but it is a delusive seeming. The temporary adoption of such expedients, when contrary to the inexorable requirements of far-seeing or sympathetic justice, will always degrade, and in the end destroy, the society which persists in resting upon expediency instead of principle. For this reason slavery and polygamy are always found to hinder the progress of any nation that is founded upon them. In our own country the unjust condonation of adultery, by law, in 1857, against the strenuous opposition of far-seeing statesmen, has educated more than one generation in a false and degrading idea of physiology. In all sanitary legislation, where the authority of the medical profession is recognised by an appeal to any of its members for guidance in respect to practical regulations, the counsel given affects the honour of the whole profession, and it is vital to the authoritative status of the profession that the advice rendered shall be based upon a sound knowledge of the creative laws which govern our complex human nature. Superficial or one-sided statements, made on so momentous an occasion as an appeal by legislation to medicine, degrade the profession; and practical measures founded upon unsound knowledge may debase legislation and intensify the evils they are intended to diminish. The most serious of all the subjects on which the advice of the medical profession is required concerns the legislative enactments or municipal regulations which affect the relations of the sexes. The importance of these relations cannot be overrated. They deal with the very source of society. They may affect the soundness of both body and mind. If legislation fosters immoral customs which spread disease and death, then such legislation, corrupting a nation’s life, is treachery to human nature, and the false counsel that has been given is defiance of Divine law.