DUTROCHET, RENE-JOACH1M-HENRI, a distinguished French botanist and natural philosopher. Ho was born at the Chateau de Mon, Poitou, on the 14th of November 1776, and died at Paris on the 4th of February 1847. He was the son of a military officer, who emigrated, and whose property was confiscated. Young Dutrochet in 1799 entered as a private the military marine, but afterwards deserted. In 1802 he commenced at Paris the study of medicine. He made a brilliant career as a student, was created Doctor in 1806, and in 1808 was appointed physician to Joseph Bonaparte, king of Spain. He became principal physician to the Hospital of Burgos, which was then devastated with typhus. He displayed here great energy and skilL In 1809 be returned to France, and gave himself up to the study of those natural sciences for which his medical education fitted him. The tendency of Dutrochet's mind was to develops the laws which regulated the existence of organic beings, and many of his researches have had a permanent influence on the development of the departments of science to which they relate. His name is best known to physiologists from his researches on the passages of fluids through animal and vegetable membranes. The laws which he observed to regulate these phenomena he applied to the explanation of the functions of absorption and excretion in the animal and vegetable body. The passage of a fluid from without inwards be called endoamosis; and the passage from within outwards exosmosis' Ilia views on this subject were published in a work which appeared both In London and Paris in 1828, with the title 'Nouvelles recherches sur rEndosmose et l'Exosmose, suiviea de l'application exp6rimentale de ces actions physiques b la solution du probleme do l'irritabilit6 v6g6tale et k Is determination de la cause de l'ascension des tiger, de Is descente do seines.' The phenomena comprehended under the
terms endoamose and exosmose were rightly described by Dutrochet, but he was hasty in tracing their cause to electricity, and failed tc ee that they were parts of a much more general set of phenomena .han he had described. His other papers are very numerous, and yore on a variety of subjects not immediately related. Thus we find its inquiries embraced amongst other things the following subjects : s New Theory of Voice ; a New Theory of Harmony ; on the Family of sVheel-Animalcules; History of the Egg of the Bird ; on the Envelopes )f the Foetus; Researches on the Metamorphosis of the Alimentary :anal in Insects ; on the Structure and Regeneration of Feathers ; m the Height of the Meteor which projected Aerolites at Charsonville n 1810; on the Growth and Reproduction of Plants ; on the Special Directions taken by certain parts of Plants. The results of all his abours and a connected view of the subjects to which he devoted airs attention, he gave in a volume entitled '116moiree pour servir l'Histoire Anatomique et Physiologique des Vegetaux et des kniusaux.'