PHYSIOLOGICAL CHEMISTRY FOR MEDICAL STUDENTS MAX
TRUMPER, UNIVERSITY
OP
PENNSYLVANIA, PRILADELPHIA, PENNSYLVANIA
The medical student attends classes on the average of 50 hours a week for 30 weeks a year, which is equivalent to a total of 3000 hours of preclmical instruction. Of this time he spends 150 hours in the chemical laboratory and 120 hours in lectures on chemistry. This approximates 9% of his pre-clinical studies or only 4.5% of his medical education, exclusive of his internship. Therefore, the teacher of physiological chemistry must concentrate on the fundamental principles of chemistry in order to enable the student to understand and apply this tool to medicine. The immediate duty of the teacher is to teach the chemistry which has a direct bearing on medical problems and to avoid recent enthusiasms. The latter must of necessity be uncertain until the experts themselves have ceased to differ. Lectures, quizzes, and laboratory work all have their place. In the lecture the broad fundamental aspects of physiological chemistry should be taught and supplementedby well-planned demonstrations. A lecture which simply gives mere facts that can be learned from any textbook is of little help to the student. The student should be led to see the relation of physiological chemistry to other medical subjects as bacteriology, hygiene, pathology, and especially physiology. Moreover, there is a necessity for cooperation of the chemistry department with that of physiology and with the clinical laboratory since much of the subject matter dealt with in these departments overlaps. Modern chemistry is so extensive and specialized that careful selection is necessary to obtain a balanced course. The same thing is true of chemistry as of the teaching of surgery to the undergraduate student. He is not taught surgery with the idea of graduating him as a finished specialist in surgery. He is made acquainted with the general principles of surgical technic, particular emphasis being placed upon diagnosis. The student should be made sufficiently familiar with the principles of chemistry and with the use of chemical apparatus to enable him to follow and apply subsequent advances in the field of medical chemistry. One can teach only that which he knows and if the teacher of chemistry has not had hospital or clinical experience, then the student will not be instructed along clinical lines. Clinical insight requires only an intermediate chemistry and not the pure theoretical chemistry of the research worker. In this connection I quote the following from Professor Harvey Cushing's dedicatory address on February 23, 1925, a t the Yale Medical School. Fortunate is the school in which, from the outset, teaching is in terms of the future patient rather than of the present frog and guinea pig. But we clinicians, particularly those on the surgical side, begin to be a little doubtful of the existing program. We find that the two preliminary years of training in laboratory methods, conducted by teachers who themselves have had no clinical experience, fail to provide the student
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with the information, resourcefulness, and observational training that would be most useful to him in his later semesters.
Whenever teachers pride themselves on the complicated formulas which their students know, it is probable that their knowledge ends with those formulas. And when medical students are required chiefly to solve complicated chemical problems, they are receiving a one-sided training. I do not intend to detract from the value or the necessity of accurate scientific teaching, but when a medical student is showered with intricate details on recondite chemical problems then no time is left to include the practical chemistry of clinical medicine. This should include pre- and post-operative chemistry, the chemistry of water balance, normal and abnormal nutrition and metabolism, the biochemical factors in pregnancy, the biochemical mechanisms in acidosis and alkalosis. The study of diet should include the inorganic constituents as well as the ketogenic-antiketogenic calculations. The primary object of teaching is to find our way into the mind of the student and fix there the fundamental methods of acquiring scientific knowledge, supplemented by a working knowledge of the chemical necessities of the practicing physician and surgeon. The student should be given selected materials and methods which he can understand and apply. The theoretical disputable material incident to the advances of the pure science of chemistry must be avoided. The chemistry, for instance, of the possible interactions responsible for the development of the blue color in blood uric acid analysis is uselessall that the medical student need know is the advances in blood chemistry which were made possible through colorimetry and the principles involved. The medical student who acquires a glib acquaintance with the minutiae of fundamental research is too ready to substitute theoretical interpretations for sound substantial clinical thought and observation of his patient. In the laboratory the more detailed work should be considered-here ideas are tested, methods demonstrated, and familiarity of the varied tests and apparatus obtained. Here an insight is afforded into the specific chemical alterations of the body in health and in disease. The student learns the significance as well as the limitations of laboratory tests. He should know when to have certain tests made, how to collect and to preserve the necessary specimens. Today, more than ever before, owing to the flood of chemical researches, the teacher must judge critically the literature. Any chemist with clinical experience knows the too frequent assumptions that are made in transferring to the patient experimental studies made on animals. The mind of the student may be confused unless care is exercised in labeling experimental data and stressing their limitations. The complicated chemical subjects such as H-ion concentration, colloid chemistry, enzymes, and acidbase equilibrium can be presented in their physiological application with
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more benefit to the student than if they were discussed from the abstract standpoint of the test tube and the reagent bottle. Chancellor Avery of the University of Nebraska has said: If I were teaching chemistry in a medical school, I would try to show the connection between chemistry and medicine even while teaching the subject as a general scientific course, thus stimulating the students' interest in chemistry through suggcstions of its importance t o their future work.
In thus emphasizing the importance of applied medical chemistry, I have assumed the knowledge of the principles of chemistry to be a prerequisite of the medical course. The present trend is to increase the pre-medical requirements in chemistry and this fact makes all the more important and all the more certain that the future chemistry of the medical school shall be definitely clinical chemistry. The work for the freshman year should be restricted as far as possible to the chemical composition of the body tissues and fluids with a thorough consideration of the chemistry of foods, their digestion, absorption, and excretion. The work in the second year should be of a more advanced nature involving quantitative analyses of blood and urine in normal and pathological conditions. Particular attention should be given to intermediate metabolic principles which will enable the student to understand and apply the various clinical laboratory procedures to distinguish functional disorders from pathologic ones. The course offered to the freshman medical student should include the following: 1. Principles of physical chemistry in their application to physiological chemistry, including colloid chemistry. 2. Thorouah presentation of enzymes and enzyme action. ~. 3. Foodstuffs: carbohydrates, proteins, fats and lipoids, vitamins, inorganic. 4. Digestion: salivary, gastric, pancreatic, intestinal, bile. 5. Ahsaption. 6. Composition of blood and lymph. 7. Add-base equilibrium. 8. Excretions: urine, feces, perspiration. 9. Human and cow's milk. 10. Tissue chemistry: epithelial, connective tissue, teeth, muscle, nerve,bone, etc. 11. Spinal fluid. 12. Putrefaction products.
The following should be considered for the sophomore year: 1. Resume of digestion and absorption. 2. Intermediate metabolism (normal and pathologic), protein, fat, carbohydrate, inorganic, lipoids. 3. Quantitative blwd analysis (normal and pathologic). 4. Quantitative urine analysis (normal and oatholoaic). . . 5. water metabolism including water balan& 6. Vitamins, hypervitaminosis, and avitaminosis.
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7. Chemistry of the endocrines. 8. Energy metabolism (normal and pathologic) 9. Gastric analysis. 10. Disturbances of acid-base equilibrium.
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