During these early years Laennec devoted himself particularly to the study of pathology. Like all the men who {152} have made great discoveries in medicine he understood that all true medical advance must be founded on actual observation of the changes caused by disease in the tissues, and that this knowledge can only be obtained in the autopsy room. For years he devoted himself to the faithful study of the tissues of patients dead from various forms of disease. He wrote as the result of this work a treatise on peritonitis that was a distinct advance over anything known before his time and which, in the words of Benjamin Ward Richardson, "as a pathological study was shrewdly in anticipation of the later work of one who became his most formidable rival, the famous Broussais." From the peritoneum his attention was attracted to the liver. As early as 1804 he wrote a description of the membranes of the liver. Pathological changes in the liver continued to occupy his attention for some time, and it is to him we owe the name cirrhosis of the liver, as a term for the changes which are produced by alcohol in this gland. Alcoholic cirrhosis is often spoken of as Laennec's cirrhosis of the liver, and he was the first to point out the significance of the changes in the organ, their etiology and the reason for the symptoms that usually accompany this condition. This work alone would have been sufficient to have made Laennec's name a permanent fixture in medical literature. During the early years of Laennec's career at Paris, the French Anatomical Society was founded and Laennec became a prominent member of it. Corvisart, who was the moving spirit in the society, was at this time--the early years of the nineteenth century--doing his great teaching at the medical school of the University of Paris. He was Laennec's master, and was at the height of his glory. It was a constant source of surprise to his students to note how well the master's diagnosis agreed with postmortem findings. This is, after {153} all, the only true criterion of scientific diagnosis. It is not surprising that the strict application of this practical method of control of medical theory soon gave rise to a series of distinct advances in medical knowledge of the greatest importance. Discussions of cases were frequent and Laennec took a prominent part in them. His knowledge of medicine was broadening in this great field of practice, and he was chosen as one of the contributors to the _Dictionnaire des Sciences Médicales_. His articles for this work contained much original matter of great value and suggestive views of notable importance. Laennec was the first to give a description of carcinoma encephaloides and certain especially malignant forms of cancers. He showed the distinction between pigmented spots of benignant character and those that were due to malignant disease.