"In investigating the seats of disease, Morgagni is not content to record the coincidence of a lesion in an organ with the symptoms apparently due to disordered function in that organ. "For the first time almost in medical inquiry, he insists on examining every organ, as well as the one suspected to be chiefly implicated; not only so, he marshals with the utmost care, from his own experience and that of his predecessors, all the instances in which the symptoms have existed apart from the lesion, or the lesion apart from the symptoms. He discusses each of these incidents with severe exactness in the interest of truth, and only after an exhaustive investigation will he allow the inference either that the organ referred to is or is not the seat of the disease. "And in like manner in dealing with causes: a group of symptoms may be caused by certain organic changes--it may be even probable that it is so--but, according to Morgagni's method, we must first inquire into all the lesions of {31} organs which occur in connection with such symptoms; in the second place, we must know if such lesions ever occur without the symptoms; and again if such symptoms can be attributed in any cases to other causes in the absence of such lesions." During over sixty years of a long life Morgagni continued to follow out the idea that he had developed as a boy, and his works contain the first definite account of pathological lesions and clinical manifestations that attracted attention. As a proof of the striking difference between the value of observation and theory in medicine, it may be said that many hundreds of volumes containing the most elaborate medical theories were published during the eighteenth century, and that practically none of these is ever read now, except for curiosity's sake by some seeker after the quaint and distant in medicine, while Morgagni's books still contain a precious fund of information, to which pathologists at least, and not a few clinicians, turn often with interest and come away always with profit. They are not infrequently quoted from, and, as we shall see, have been highly appreciated by some of the best medical authorities of the present and the immediately preceding generations.