Charles Edward Brown-Sequard, a French -American physiologist, born in the island of Mauritius in 1818. His father, Edward Brown, was a native of Philadelphia, and at one time commanded an American merchant vessel. He was lost at sea, in an attempt which he had volunteered in an old and badly found vessel to procure provisions for Mauritius, at that time suffering under famine. His mother, from whom he derives the name Sequard, was a French woman. Young Brown-Sequard was carefully educated in his native island. In 1838 he went to Paris to complete his studies, and received there the degree of M. D. in 1840. Since that time he has devoted his attention mainly to experimental physiology. He has had a prize awarded him five times by the French academy of sciences, and he has twice received a part of the queen's grant for the encouragement of science from the royal society of London. He visited the United States several times, and delivered courses of lectures before various scientific bodies, illustrating his doctrines by the most delicate vivisections. His experiments on the blood give great support to the doctrine that the fibrine of that fluid is an excrementitious product, and not subservient to nutrition.
He has produced all the life-giving effects of the natural blood by the transfusion of defibrinated blood. By the injection of oxygenated and defibrinated blood the irritability of the muscles was restored some time after the occurrence of post-mortem rigidity, and the blood returned by the veins venous in color and containing fibrine. Defibrinated and oxygenated, it was again injected by the artery, and thus the same blood was used for hours in maintaining the irritability of the muscles. Arterial blood, according to him, is subservient to nutrition, and maintains the irritability of the muscles; venous blood is necessary to produce muscular contraction. By his experiments on animal heat the temperature in mankind is placed at 103° F., several degrees higher than by previous observers. When animals are asphyxiated their temperature at the time exerts a great influence on the duration of life. Previous observers had noted that certain poisons cause a rapid diminution of the animal temperature; according to Brown-Sequard, when the animal heat is maintained by artificial means, the toxic action is much diminished.
The great discovery of Sir Charles Bell of the respective sensitive and motor functions of the anterior and posterior roots of the spinal cord, directed the attention of physiologists to that subject. After numerous and apparently contradictory experiments, the conclusion was generally acquiesced in that the posterior columns of the cord are sensitive, and convey sensations to the brain; that the anterior are motor, and convey the influence of the will to the voluntary muscles; and that the gray matter of the cord serves merely to reflect impressions from the sensitive to the motor nerve roots. As the result of numerous ingenious experiments, Brown-Sequard concludes that the sensitive fibres do not communicate directly with the brain, but convey impressions to the gray matter of the cord, by which they are transmitted onward to the brain, and that their decussation or crossing takes place in the cord itself, at or near the point at which they enter, not in the cerebrum or medulla oblongata. On the other hand, the anterior or motor fibres pass on directly to the brain, effecting their decussation in the medulla oblongata; the gray matter receives the impressions, conducts them to the brain, or reflects them upon the motor nerves, but is itself insensible to ordinary stimuli.
These views enable us to understand some rare and curious facts in pathology which otherwise would remain inexplicable. Other researches of Brown-SSquard relate to the muscles, to the sympathetic system of nerves, to the effect of the removal or destruction of the supra-renal capsules in animals, etc. In May, 1858, he delivered a course of lectures on the nervous system before the royal college of surgeons at London, which attracted much attention. In 1864, having taken up his residence in the United States, he was appointed professor of the physiology and pathology of the nervous system in the medical department of Harvard university, a position which he held till 1868. In 1869, becoming again a resident of France, he was appointed professor of experimental and comparative pathology in the school of medicine at Paris. In 1858 he founded the Journal de la physiologie de Vhomme et des animaux, which he made from the beginning a leading journal of physiology, and which he continued to conduct as editor till 1863. On his return to France in 1869 he established the Archives de la physiologie nor-male et pathologique, a journal of similar standing with the preceding.
He has been a frequent contributor of scientific articles to the journals under his charge, and Iras also been much engaged as consulting physician for diseases of the nervous system. In 1873 he established himself as a practitioner in New York, and in conjunction with Dr. E. 0. Seguin began the publication of a medical journal entitled " Archives of Scientific and Practical Medicine."