logical anatomy clinical classification was impossible, and without physiology and the methods of the physiologist, clinical interpretation was difficult. The influence of pathological anatomy on clinical medicine was felt first in England through Baillie (1761-1823), a pupil of Hunter; in France, after Bichat, through Louis, Andral and Lænnec; in Germany through Schonlein and Romberg; and in America through the pupils of Louis. The discovery of the diseased conditions with which we associate the names of Bright, Pott, Addison, Graves, Stokes and Hodgkins came at this time, as also Marshall Hall's discrimination of diseases of the spinal cord and Bayle's study of tuberculosis of the lung. It was the period when the best members of the profession endeavored to give to the study of symptoms the same precision as characterized anatomical observation and to combine the results of this method with the revelations of pathological anatomy. It was this method that culminated in Louis's so-called "numerical or statistical method," the method of basing conclusions on large groups of records rather than on isolated observations, and which, in this country, through the work of two of Louis's students, Gerhard and Stillé, led to the differentiation of typhoid fever from typhus fever, with which it had been confounded.
But of equal importance was the second influence which was at work, that of improved methods of diagnosis of diseases of the heart and lungs, the methods of percussion and auscultation. Percussion was first used by Auenbrugger, in 1761, but was treated with contempt and ridicule until 1808 when his pamphlet was translated into French by Corvisart, who proclaimed the value of the method and obtained for it universal recognition. Shortly after, in 1819, came Laennec's work on the use of the stethoscope in auscultation, and Skoda in 1839 did much to extend the use of both percussion and auscultation.
This phase of medicine, the development of instruments and means of studying diseases of the internal organs and the organs of the special senses—the history of the stethoscope, the ophthalmoscope, the laryngoscope, and like instruments—is a most fascinating subject and one worthy of extended treatment, but it must suffice here to state that the new methods of direct exploration brought about a complete revolution in the knowledge of disease and had "more influence on the development of modern medicine than all the 'systems' evolved by the most brilliant intellects of the eighteenth century." (Payne.)
Exact clinical observation, the study of pathological anatomy and the increasing use of instruments and methods tending to accuracy in diagnosis were, therefore, the characteristic features of the early nineteenth century school of medicine. Both medicine and surgery were
douloureux; of prison and camp fevers by Pringle, of epidemic fevers by Husham; of diseases of the skin by Willan, of angina pectoris by Heberden, and of gastric ulcer by Baillie.