What then is man’s position to-day, and what is his danger? His position is this. In emerging from the contest with nature he has ceased to be a natural animal. He has evolved curious powers of discrimination, of choice, and of construction. He has changed his environment, his food, and his whole manner of living. He has enquired into the laws which govern heredity and into the causes of disease. But his knowledge is still limited and his emergence incomplete. The power of the force we know as evolution still holds him in chains, though he has loosened his bonds and may at last free himself entirely. Thus we come to man’s danger. Evolution—a term we use here and elsewhere in this connection as that which is best understood to indicate the whole operation of natural selection and all that it connotes—has two clearly defined functions; by one of these it develops, by the other it destroys. By an infinitely slow action it has developed such wonders as the human eye or hand; by a process somewhat less tedious it allows any organ that has become useless to perish, such as the pineal eye or (in process) the vermiform appendix, and, if we can estimate the future course, the teeth and hair. By the change he has effected in his mode of life, man is no longer necessarily dependent upon his physical organism for the means of his subsistence, and in cases where he is still so dependent, such as those of the agriculturist, the artisan, and others who earn a living by manual labour, he employs his muscles in new ways, in mechanical repetitions of the same act, or in modes of labour which are far removed from those called forth by primitive conditions. In some ways the physical type which represents the rural labouring population is, in my opinion, even more degenerate than the type we find in cities, and mentally there can be no comparison between the two. The truth is that man, whether living in town or country, has changed his habitat and with it his habits, and in so doing has involved himself in a new danger, for though evolution may be cruel in its methods, it is the cruelty of a discipline without which our bodies become relaxed, our muscles atrophied, and our functions put out of gear.