formulæ, and the doctor who is so fortunate as to own one of these books is held in high repute for his superior learning, notwithstanding he may not be able to decipher a line of it. Practically, the Laos, so far as the average doctor is concerned, have no medical treatises.
The Laos are without a definite knowledge of any of the organs or functions of the human body; no Harvey or Sylvius has ever arisen among them. All of their theories concerning the bodily functions and the four elements are merely philosophic guesses. Imagination has taken the place of reason and experiment. Speculation furnishes them with a satisfactory solution of the problem, "Why is it that instead of flesh (muscles) only, tendons are found in the human body?"
The Laos divide diseases into two classes. The first class includes all those disorders which may be considered as simply disturbances of equilibrium caused by an undue preponderance or diminution of one of the four elements—wind, fire, earth and water; the second class embraces all those more serious disorders of the human system which are due directly or indirectly to the influence of offended spirits.
The Laos materia medica embraces a considerable variety of medicines, nearly every one of which is supposed to be a specific in some disease; and, although his ideas of the medicinal
