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JAMA 100 Years Ago
July 26, 2000


Author Affiliations

JAMA 100 Years Ago Section Editor: Jennifer Reiling, Editorial Assistant.

JAMA. 2000;284(4):411. doi:10.1001/jama.284.4.411


I believe that the vast majority of the practitioners of medicine never make an examination of the blood of their patients unless such an examination is suggested and carried out by a consultant. The reasons for this may be many, but the following I believe to be the most important: 1. Blood examinations as practical diagnostic measures are of comparatively recent origin; consequently, men who graduated fifteen or more years ago were not taught the value of such examinations, or how to make them. Unless such members of our profession have had the subject forced upon them by teaching, or by continued intercourse with men trained in such work, they are quite unlikely to take it upon themselves. 2. Blood examinations, like all other valuable diagnostic measures take time. The general practitioner is hurried; in the town competition is great; and those who depend upon the practice of medicine for a livelihood are apt to become careless about the use of these finer diagnostic measures, and depend upon less certain means of diagnosis. To once slur these valuable agents is to learn to gradually discard them, to the great detriment of ourselves and our patients. It is certain that in many cases examination of the blood is quite as important as, indeed more important than, examination of the urine. It is now an accepted fact that no case is thoroughly studied without a urine examination. I believe it will soon be accepted by the general practitioner—as it is now recognized by the specialist—that a blood examination is equally as important for a thorough study of our cases.

That such examinations are possible and practical for one who practices medicine for a livelihood and not as a pastime, I am personally certain, for I am a practitioner and by no means a hematologist; I have been slow in learning, but now make almost daily use of this most valuable help. Without the aid of an assistant, I have made the examinations of blood in a practical way just as I have the urine, and I feel that it helps me as much in my daily work. I have as yet been unable to examine the blood of every patient, but I trust that the time is not far off when I can do that in my work. I do, however, use blood examinations in every obscure case, with the greatest possible benefit. I was led to the general use of examination of the blood by the recognition of my own mistakes and by the mistakes of others where no such examinations were made. . . .

For years malaria has been made the scapegoat for all conditions of the character of which we may be uncertain. Every patient with an intermittent fever associated with malaise of uncertain origin—especially if such a patient resided in a malarial district—was said to be suffering from malaria. Malaria is to-day one of the few diseases that can be positively diagnosed. I believe that no case should be diagnosed as malaria unless the plasmodium malariæ has been found in the blood. Examinations for this organism need a microscope and the knowledge how to use it. Unfortunately the blood is not frequently submitted to this test. If this were done, beginning cases of tuberculosis and intermittent fevers in pneumonia would be much less frequently called malaria. . . .

It will be seen that I have not referred to the staining of the blood and the invaluable and often absolutely necessary steps toward the full study of the case. I have avoided this because such steps need a special training and familiarity with methods not always practicable in everyday practice. But if the preliminary and frequently entirely satisfactory steps be taken, then almost invariably some one can be found who will complete the examinations. The apparatus to be used in this means of diagnosis which I advocate are a microscope, slides, coverslips, hemoglobinometer and hemocytometer.

By the use of a microscope and a slide of fresh blood, one may observe, 1, whether the leucocytes are largely increased in number; 2, whether the red cells form properly in rouleaux, and whether they are of odd shapes; 3, the presence or absence of malarial organism. The first two observations may be made with an ordinary 1/6 objective. The last requires a higher power, preferably an oil-immersion. . . . It takes but a few minutes—fifteen—at a patient's home to get the blood properly. The counting and examination can be done at leisure at home. Then, too, there is no undue display of instruments in the presence of the patients. The fresh blood may be preserved for several hours by using oil of cedar run under the edge of the slide. The diluted blood in the tubes can be easily preserved by putting an ordinary gum band lengthwise about them.

In conclusion, let me insist that this most valuable diagnostic measure is practicable for the ordinary, every-day physician. It will enable him to avoid many errors in diagnosis. It will help him to take a deeper, more scientific interest in his cases.

JAMA. 1900;35:228-230