Page:Popular Science Monthly Volume 28.djvu/557

Rh This doctrine of the independence of the will is regarded as one of the distinguishing characteristics of the philosophy of the treatise, running "through the entire work as the one grand exception among a series of physical sequences, interdependent, and standing to each other in the relation of cause and effect, of antecedent and sequent." Another important feature of the book is found in its discussions of the subjects of mesmerism, spirit-rapping, table-turning, and the like, in which the author's philosophical spirit is eminently displayed. He set himself soberly at work to find out what is true in these manifestations, and to verify the facts, and explain on rational grounds those which were susceptible of explanation, while "he did not hesitate to denounce those he thought were due to insincerity or fraud." He found the key to such of the phenomena as are real in what he called ideo-motor action, which he defined to be "the direct manifestations of ideational states, excited to a certain measure of intensity, or, in physiological language, reflex actions of the cerebrum." His observations on this branch of the subject were also published separately in the work "Mesmerism, Spiritualism, etc., historically and scientifically considered."

Dr. Carpenter's appointment to the office of Registrar of the University of London, in 1856, gave him more leisure than he had previously enjoyed to pursue his studies systematically and untrammeled by the drudgery of routine duties; and the fruits of the employment of this leisure are seen in the greater fullness and perfection of his scientific work subsequent to that time. He had already, during most of his residence in London, been occupied with the minute study of the calcareous shells of the Mollusca, and this had led him to the regular use of the microscope. One of the earlier fruits of these studies was his book on "The Microscope and its Revelations," a manual most highly prized by all followers of the enchanting study of microscopy, of which the sixth edition was published in 1881 Other fruits of them are to be found in his reports on the microscopic structure of shells, which he presented to the British Association from 1844 onward. In these papers much light was thrown on the structure, which was found to be more complex than had been supposed, and the law of growth of shells. His studies in the Foraminifera, which were continued through his life, furnished the occasion for several memoirs in the "Philosophical Transactions," and for an illustrated monograph, which was published by the Ray Society in 1862. One of the most interesting of his studies in this line was that on the structure and development of the Comatula, or feather-star, in which he proposed a theory of the nervous function of the axial cords running through the arms of the animal, differing from or contradicting the views commonly held. A re-examination of the structure of the animal, and repetition of his experiments, made some five years ago at the Marine Laboratory of Dr. Dohrn, at Naples, and the experiments of other naturalists, have given confirmation to his opinion. Pertaining