BICHAT, MARIE-Finscots-XANIER, a celebrated French anatomist and physiologist, was born at Thoirette in the department of Ain, in 1771. His father, who was himself a physician, was his first instructor. He entered the College of Mantua, and afterwards studied at Lyons. In . mathematics and the physical sciences he made rapid progress. Becoming passionately fond of natural history he -ultimately devoted himself to the study of anatomy and surgery, under the guidance of Petit, chief surgeon to the dlotel Dieu at Lyons. He resumed for a time his early -studies, restricting himself, however, within such limits as did not interfere with his medical pursuits. Petit soon discerned the superior talents of his pupil, and, although the latter had scarcely attained the age of twenty, employed him constantly as his assistant. The revolutionary disturbances compelled Bichat to fly from Lyons and take refuge in Paris about the end of the year 1793. He there became a pupil of the celebrated surgeon Desault. One clay, volunteering to supply the place of an absent pupil who was to have recapitulated the lecture of the day before, he acquitted himself so admirably that Desault was strongly impressed with his genius ; and from that time Bichat became an inmate in his house, and was treated as his adopted son. For two years he actively participated in all the labours of Desault, prosecuting at the same time his own researches in anatomy and physiology. The sudden death of Desault in 1795 was a severe blow to Bichat. His first care was to acquit himself of the obligations he owed his benefactor, by contributing to the support of his widow and her son, and by conducting to a close the fourth volume of Desault's Journal de Chirurgie, to which he added a biographical memoir of its author. His next object was to reunite and digest in one body the surgical doctrines which Desault had published in various periodical works. Of these he composed, in 1797, the book entitled Wuvres Chirurgicales de Desault, ou Tableau de sa Doctrine, et de sa Pratique dans le Traitement des Maladies Externes, a work in which, although he professes only to set forth the ideas of another, he develops them with the clearness and copiousness of one who is a master of the subject. He was now at liberty to pursue the full bent of his genius, and, undisturbed by the storms which agitated the political world, he directed his full attention to surgery, which it was then his design to practise. We meet with many proofs of his industry at this period in the Recuell de In Societe Medicale d'Emulation, an association of which Bichat was one of the most active members. In 1797 he began a course of anatomical demonstrations, and his success encouraged ldm to extend the plan of his lectures, and boldly to announce a course of operative surgery. Bichat's reputation was now fully established, and he was ever after the favourite teacher with the Paris students. In the following year, 1798, he gave, in addition to his course on anatomy and operative surgery, a separate course of physiology. A dangerous attack of Inomoptysis interrupted for a time these heavy labours ; but the danger was no sooner past than he plunged into new engagements with the same ardour as before. He had now scope in his physiological lectures for a fuller exposition of his original views ou the animal economy, which excited much attention in the medical schools at Paris. Sketches of these doctrines were given by him in three papers contained in the Memoirs of tire Societe Medicale d'Emulation. The doctrines were afterwards more fully developed in his Traite sur lee Membranes, which appeared in 1800. In the notes to a small work, in which he gave in a condensed form the lessons of Desault on the diseases of the urinary passages, are found the germs of many of Bichat's peculiar views.

His next publication was the Recherches Physiologiques sur la Vic et sur la Mort (1800), which consists of two dissertations. In the first he explains his classification of functions, and traces the distinction between the animal and organic functions in all its bearings. In the second he investigates the connection between life and the actions of the three central organs, the heart, lungs, and brain. But the work which contains the fruits of his most profound and original researches is the Anatomic Ceirjrale, published in 4 vols. Svo in 1801.

Before Bichat had attained the age of eight-and-twenty he was appointed physician to the Hotel Dieu, a situation which opened an immense field to his ardent spirit of inquiry. In the investigation of diseases he pursued the same method of observation and experiment which had characterized his researches in physiology. He learned their history by studying them at the bedside of his patients, and by accurate dissection of their bodies after death. He engaged in a series of examinations, with- a view to ascertain the changes induced in the various organs by disease, and in less than six months he had opened above six hundred bodies. He was anxious also to determine, with more precision than had been attempted before, the effects of remedial agents, and instituted with this view a series of direct experiments on a very extensive scale. In this way he procured a vast store of valuable materials for his course of lectures on the Materia Medica, the completion of which was prevented by his death; but a great part of the facts were embodied in the inaugural dissertations of his pupils. Latterly, he also occupied himself with forming a new classification of diseases.

Bichat commenced a new work on anatomy, in which the organs were arranged according to his peculiar classification of their functions, under the title of Anatomic Descriptive, but he lived only to publish the first two volumes. It was continued on the same plan, and completed in five volumes by his assistants MM. Buisson and Roux. His death was occasioned by a fall from a staircase at the Hotel Dieu, which threw him into a fever. Exhausted by excessive labour, and enfeebled by constantly breathing the tainted air of the dissecting-room, he sank under the attack and died on the 22d July 1802, attended to the last by the widow of his benefactor, from whom he had never been separated. His funeral was attended by above six hundred of his pupils, and by a large number of the physicians of Paris. His bust, together with that of Desault, was placed in the Hotel Dieu by order of Napoleon.