critique on that portion of Whewell's "History of the Inductive Sciences" which relates to physiology; and by an article on his favorite subject, "The Physiology of the Spinal Marrow," where the writer discusses the doctrine of reflex action which Dr. Marshall Hall had recently propounded as new. These are tolerably good beginnings for a young man of twenty-four years.
An impulse and direction were given to Mr. Carpenter's studies about this time, by his becoming possessed of a microscope, which a prize of thirty pounds, gained at Edinburgh University in 1837, for the best essay of that year, enabled him to purchase. He had already formed, and begun to execute, his design to write the now famous treatise entitled "General and Comparative Physiology," the first edition of which appeared in 1838. The scientific reader will not need to be told the general character of this work; and any account of it, to be of use to the non-scientific reader, would transgress the limits of this biographical sketch. Dr. Carpenter confesses that the course of study he had to go through in bringing out the work was of immense service to him, though it was rather detrimental than otherwise to success in the practice of his profession.
Up to this time the subject of this memoir had not received the degree of M. D. According to one of the regulations of the University of Edinburgh, a three-years' attendance was requisite for graduation; and when Mr. Carpenter accepted the post of lecturer at the Bristol Medical School he had only completed his second year. Now, however, a change in the rules enabled him to graduate in 1839 by an additional residence of three months. His thesis on the occasion of taking his degree—"On the Physiological Inferences to be deduced from the Structure of the Nervous System of Invertebrated Animals"—gained for its author one of the gold medals annually distributed. The views advanced by the essayist, though meeting with some opposition for a time, were at once adopted by Prof. Owen and others, and have since passed into general acceptance among scientific men.
The scientific aspects of medicine having from the beginning possessed attractions superior to the strictly practical, Dr. Carpenter resolved to devote himself wholly to the study of physiology, the delivering of lectures, private tuition, and writing. On being appointed Fullerian Professor of Physiology in the Royal Institution, he resigned his post in the Bristol Medical School, and came, in 1844, to London, where he has resided ever since. Hitherto he had been engaged chiefly in reducing to system the results of the investigations of others; as in his "Comparative Physiology," and "Human Physiology," the latter of which first appeared during this year. But about this time he began to be known as an original investigator, in connection with his researches into the microscopic structure of the shells of Echinodermata, Mollusca, Crustacea, etc. He was elected a Fellow of the Royal So-
