Quantitative analysis is important in another way. It gives valuable training to the hand and eye, and develops a particular form of accuracy which is required in biochemical work, and which enables the student to interpret justly the work of others.
Physical chemistry to-day contains a mass of material of the highest importance in all branches of biological science. An elementary acquaintance with it is essential for understanding such subjects as the physiology of the blood and the functional activity of the kidney and lung, since it explains the nature of solutions and the conditions governing the passage of substances through membranes.
Many medical schools require for entrance, work in general chemistry and qualitative analysis, and a few call for organic chemistry. These are essential. A half course in quantitative analysis and a half course in physical chemistry are desirable.
Physics.—Many students who are careful to take courses in biology and chemistry in preparation for medicine neglect physics entirely, or think that the elementary work done for admission to college is sufficient. A thorough college course, with laboratory work consisting of accurate measurements, is necessary for certain branches of medical practise and for the fundamental study, physiology. Physics is related to physiology in many ways. In studying muscular contraction the elements that constitute mechanical work and the action of levers should be known. For the study of the circulation it is necessary to understand the principles of hydraulics and the transmission of pressure in fluids; the laws of osmosis (studied in physical chemistry) aid in interpreting the diffusion of fluids between vessels and tissues. In considering the constructive and destructive changes in the body, the principle of the conservation of energy should be kept constantly in mind. To understand the maintenance of normal temperature and the changes in fever, some knowledge of the physics of heat is needed. An understanding of electricity is necessary for explaining the electrical changes produced in living tissues, and in order to stimulate tissues experimentally so that their activities may be studied. Electrical stimulation is used in treating certain diseases, and the physiological laboratory contains many pieces of electrical apparatus. The importance of the X-ray in medicine is sufficiently well known. In order to understand vision and the application of lenses to the eye, the principles of reflection and refraction must be understood. The nature of sound and its transmission through various media is similarly related to the physiology of hearing. It is a serious mistake to begin work in a modern laboratory of physiology before taking a thorough college course in general physics.
Mathematics.—The value of mathematics for medicine is indirect, since it is required chiefly in preparation for physics. The student