Monopoly is one of the most formidable enemies of American liberty. It is now assuming the form of "Trust" combinations to raise prices, but there is no monopoly so grasping as the medical,--none which assumes to suppress competition by law. The plea of promoting education is as false as a proposal to elevate the pulpit by compelling every clergyman to pass through a Roman Catholic college. The existing medical colleges hold the same relation to the practice of the healing art as the Sectarian Theological Seminary to the practice of Christianity. One may be a very good Christian without the help of a theological seminary, or a very good doctor without the help of a medical college, but no one can be a first-class physician who goes through a medical college and adheres strictly to all the knowledge and all the ignorance administered by professors, without learning anything from other sources. MAYO'S ANAESTHETIC. The suspension of pain, under dangerous surgical operations, is the greatest triumph of Therapeutic Science in the present century. It came first by mesmeric hypnotism, which was applicable only to a few, and was restricted, by the jealous hostility of the old medical profession. Then came the nitrous oxide, introduced by Dr. Wells, of Hartford, and promptly discountenanced by the enlightened (?) medical profession of Boston, and set aside for the next candidate, ether, discovered in the United States also, but far inferior to the nitrous oxide as a safe and pleasant agent. This was largely superseded by chloroform, discovered much earlier by Liebig and others, but introduced as an anaesthetic in 1847, by Prof. Simpson. This proved to be the most powerful and dangerous of all. Thus the whole policy of the medical profession was to discourage the safe, and encourage the more dangerous agents. The magnetic sleep, the most perfect of all anaesthetic agents, was expelled from the realm of college authority; ether was substituted for nitrous oxide, and chloroform preferred to ether, until frequent deaths gave warning.