“In whatever faculty one desires to acquire a degree and obtain success, he should, besides regarding the soul and the diseased body of the patient, exert himself to obtain a thorough knowledge of that department, and be taught more by his own intuition and reason than by what the patient can tell him; he ought to be able to recognise the cause and origin of the disease which he treats, and his knowledge ought to be unwavering and not subject to doubts.” (“Paramir.,” I., Prolog.) There are, therefore, in each of these classes three grades to be distinguished, namely: (1) those who possess the full requirements of their art; (2) those who have attained only mediocrity; (3) dunces, pretenders and frauds; to which belong the vast array of licensed and unlicensed quacks, such as thrive upon the ignorance and credulity of the people and by means of their poisons and drugs “kill annually more persons than war, famine and the plague combined.” But neither of these five classes of physicians should regard their own system as the only true one, and reject the others or consider them useless; for in each is contained the full and perfect power to cure all diseases that come from either of the five causes, and each will be successful if such is the will of the Law. I.—NATURALES. To this class belongs the vast army of what is to-day usually termed “regular practitioners,” meaning those who move in the old ruts of official medical science, from the more or less progressive physician down to the vendor of drugs. The remedies which they employ belong to the three kingdoms of physical nature, and according to the elements which they represent, may be divided as follows: 1. _Earth._—This includes all mineral, vegetable, and animal substances that may be required for medical purposes, drugs, herbs, and their preparations, chemical agents, &c. 2. _Water._—To this belongs the water cure, hot and cold baths, and whatever may be connected with it. 3. _Air._—The therapeutic results which can be accomplished by means of inhaling certain gases and vapours are at present comparatively little known, except in so far as changes of climate are resorted to for such purposes. The employment of such things as pure air, sunlight, etc., is far too simple to find full appreciation of its value by a generation whose mode of thinking is too complicated to enable them to perceive simple truths, and is therefore considered to belong rather to “hygiene” than to “therapeutics.” 4. _Fire._—To the agents belonging to this class may be counted any kind of energy, heat and cold, sunlight and the actions of its variously coloured rays,[45] physical electricity, mineral magnetism, etc., all of which have thus far received very little attention from modern medicine; while the ancients employed such remedies for the cure of many diseases.[46]