In 1733, he went to Leyden to study under the famous Boerhaave. The master was worthy of the scholar and the scholar soon made himself worthy of the master. M. La Mettrie devoted all the acuteness of his mind to the knowledge and to the healing of human infirmities; and he soon became a great physician. In the year 1734, during his leisure moments, he translated a treatise of the late M. Boerhaave, his Aphrodisiacus, and joined to it a dissertation on venereal maladies, of which he himself was the author. The old physicians in France rose up against a scholar who affronted them by knowing as much as they. One of the most celebrated doctors of Paris did him the honor of criticizing his work (a sure proof that it was good). La Mettrie replied; and, to confound his adversary still more, he composed in 1736 a treatise on vertigo, esteemed by all impartial physicians. By an unfortunate effect of human imperfection a certain base jealousy has come to be one of the characteristics of men of letters. This feeling incites those who have reputations, to oppose the progress of budding geniuses. This blight often fastens on talents without destroying them, but it sometimes injures them. M. La Mettrie, who was advancing in the career of science at a giant's pace, suffered from this jealousy, and his quick temper made him too susceptible to it. In Saint Malo, he translated the "Aphorisms" of Boerhaave, the "Materia Medica," the "Chemical Proceedings," the "Chemical Theory," and the "Institutions," by this same author. About the same time, he published an abstract of Sydenham. The young doctor had learned by premature experience, that if he wished to live in peace, it was better to translate than to compose; but it is characteristic of genius to escape from reflection. Counting on himself alone, if I may speak thus, and filled with the knowledge he had gained from his infinitely skilful researches into nature, he wished to communicate to the public the useful discoveries he had made. He published his treatise on smallpox, his "Practical Medicine," and six volumes of commentary on the physiology of Boerhaave. All these works appeared at Paris, although the author had written them at Saint Malo. He joined to the theory of his art an always successful practice, which is no small recommendation for a physician. In 1742, La Mettrie came to Paris, led there by the death of M. Hunault, his old teacher. Morand and Sidobre introduced him to the Duke of Gramont, who, a few days after, obtained for him the commission of physician of the guards. He accompanied the Duke to war, and was with him at the battle of Dettingen, at the siege of Freiburg, and at the battle of Fontenoy, where he lost his patron, who was killed by a cannon shot.