Mathurin James, a zoologist and natural philosopher, born at Fontenay-le-Comte, 3d April 1723, the son of Mathurin Brisson and Louise Gabrielle Jourdain. He was originally intended for the church, but he had acquired at an early age a taste for natural history, which was particularly encouraged by the advantage that he enjoyed of passing his holidays with the justly-celebrated Reaumur, who had an estate near Fontenay. At the age of twenty-four he had made great progress in his theological studies, and had fully qualified himself for the rank of a subdeacon; but his courage failed him at the time appointed for taking orders, and he then determined to confine himself to the study of physical sciences. Reaumur had the direction of the chemical laboratory of the Academy of Sciences, and had given up the salary attached to it to several young men in succession, whom he appointed as his assistants, and of whom Pitot and Nollet became afterwards the most distinguished. He now chose Brisson for the situation, which served him, as it had done his predecessors, rather as a step in his advancement with respect to general science, than in enabling him to pursue any objects more immediately chemical; and he followed his passion in attaching himself almost exclusively to natural history. The collection of Reaumur furnished him with ample materials for his studies, and with the principal subjects described in his works on the Animal Kingdom. The first of these was published in 1756, containing quadrupeds and cetaceous animals. It consists of simple descriptions of the different species, together with synonyms in various languages, more in the nature of a prodromus than of a complete history. His Ornithologie appeared in 1760, forming six volumes, and containing a number of well-executed plates. But upon Reaumur's death, the collection having been added to the royal cabinet, Messrs Buffon and Daubenton, the directors of that cabinet, not affording him all the accommodations that he expected, he discontinued the work, and altogether renounced the study of natural history in favour of natural philosophy.

M. Brisson had been chosen a member of the Academy of Sciences in 1759; he soon afterwards associated himself with the Abbé Nollet in delivering lectures on experimental physics, and obtained the reversion of his appointments of professor in the college of Navarre, and instructor of the royal family in natural philosophy and natural history. The subject of electricity was at this time warmly debated between Nollet and Franklin; and M. Brisson had a difficult task to perform, in discussing the merits of a mistaken friend and an overbearing opponent; but, in fact, this department of science was at that time too little understood to make it disgraceful for Nollet to be in error with respect to the utility of conductors, or for Brisson to remain neutral upon this and other similar questions. He seems, however, by no means to have adhered to the character of neutrality in his anonymous Translation of Priestley's History of Electricity, published in 1771, and accompanied by notes, which exhibit a spirit of acrimonious criticism, not at all calculated to enhance the merit of the work which he wished to introduce to the notice of his countrymen. He also attempted, in an Essay on Watersports, published in the Memoirs of the academy, to explain a variety of electrical phenomena, by means of the different currents of fluid imagined by Reaumur, but certainly with very little success.

He afterwards undertook a course of experiments on the Specific Gravity of Alcohol and Water, mixed in different proportions, which led him to a conjecture, at that time somewhat singular, that water was not a homogeneous substance. He assisted M. Trudaine and other observers in the experiments which they made on Heat and Light with the powerful lens of Bernouilli; and, in conjunction with M. Cadet, he endeavoured to disprove the opinion of Beccaria, that electricity has a power of reviving the metallic oxides. He also made experiments on the refractive powers of fluids which might be substituted for flint glass in the object-glasses of telescopes; on the utility of different kinds of steel for magnetic purposes; and on the mode of renewal of the shells of some species of snails.

In 1772, M. Brisson published a memoir on the Specific Gravities of Metals, a subject which, in all its extent, occupied a great portion of his attention during twenty years of his life. The results of his experiments on a great variety of substances were collected into a single volume of Tables of Specific Gravities, which was published in 1787. It was principally for the use of students who attended his lectures that he published his Traité de Physique and his Dictionnaire, both of them containing elementary and popular information, rather calculated exclusively for the immediate purpose which they were intended to serve, than for being of permanent utility in the promotion of the sciences. At a late period of his life he renewed his attention to the subject of chemistry, when the discoveries of his junior contemporaries had given greater certainty and precision to its laws; and his last work was an Elementary Treatise on that science, intended for the use of his pupils in the central school.

His whole life was occupied in his studies, and the history of his various works comprehends the history of everything that is to be recorded concerning him. After eighty years of uninterrupted activity of mind, an attack of apoplexy reduced him to a state of second childhood, and effaced from his memory all traces even of his native language, except a few words of the dialect of Poitou, which he had spoken when he was a boy. He died on the 23d of June 1806, and his place in the academy was filled by M. Guy-Lussac. (Delambre, Mem. Inst. par. vii. Hist. p. 189.)