Medical diagnosis : with special reference to practical medicine a guide to the knowledge and discrimination of diseases / by J.M. Da Costa.

Da Costa, J. M. (Jacob Mendes), 1833-1900.

Date:: 1900

Credit: Medical diagnosis : with special reference to practical medicine a guide to the knowledge and discrimination of diseases / by J.M. Da Costa. Source: Wellcome Collection.

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$of one ailment from another. In a study of this kind, an inves- tigation of symptoms plays unavoidably a prominent part. In truth, the detection of disease is the product of close observation of symptoms, and of correct deduction from those symptoms. The first requirement therefore for an accurate diagnosis is to learn to recognize morbid signs. But the art of observation this implies is not easy, and cannot be thoroughly acquired except by practice. No one aspiring to become a skilful observer can trust exclusively to the light reflected from the writings of others : he must carry the torch in his own hands, and himself look into every recess. The knowledge obtained from reading is, however, serviceable in this way : it aids in overcoming one of the main difficulties at first experienced,—to know where to look and what to look for. There are in almost every affection some symptoms Avhich can hardly escape the merest beginner; but also some which do not appear on the surface, and which to find taxes the skill of the experienced physician. And it is especially in this search after hidden signs that medical information as well as cul- tivated tact is demanded. Now, to recognize the manifestations of disease, whether they are or are not readily pei'ceptible, we have to employ our eyes and eai's, our sense of touch and of smell. Formerly we could go no further than these senses unassisted would carry us. But science has lent its aid, and furnished means by the help of which we can detect clearly what before we could not detect at all, or that of which at best we caught only a glimpse. We now possess instru- ments by which we ascertain with accuracy the size of organs and their play. With thermometers we tell to a fraction of a degree the heat of various parts of the body. Specific-gravity bottles, and other measures devised for the purpose, inform us of the relative gravity of fluids. The microscope gives at a glance insight into matters which the naked eye fails even to perceive, shows us crystals in secretions, enables us to count the corpuscles in the blood, and to detect minute and disease-causing specific organisms. The laryngoscope demonstrates the appearance and the movements of the organ of speech. The ophthalmoscope informs us of the state of the vessels in the brain. And chem- istry, with its marA^ellous teachings, is rendering our knowledge of many morbid states amazingly complete. Then the sagacity$