Page:Popular Science Monthly Volume 9.djvu/268

248 between the circulation in animals and plants, but that in animals devoid of pulsatile vessels and hearts it is in some senses identical, and traceable to the operation of the same forces."

The subject of the circulation in animals occupies the bulk of the book, that of the invertebrates, as being in some sense intermediate between plants and the higher animals, being treated first. In a number of the lowest of these no trace of a circulation has yet been detected, the nutritious fluids in such cases being supposed to pass from the alimentary canal by interstitial transudation throughout the entire body, as the sap passes into the substance of cellular plants. A step in advance is observed where, as in the polypi, medusæ, etc., the alimentary canal is of large size and ramifies in every part of the body, serving at the same time as a circulatory and alimentary apparatus. The next advance is the appearance of distinct vessels, minus contractile power, as in plants. Vessels possessing contractile power, but without any distinct contractile organ, are next found; and afterward the heart appears, increasing in complexity of structure along with the related organs, until its highest development is reached in the mammalia.

On the subject of the forces which give rise to the circulation in the higher animals, the author, while admitting that a large share of the work is done by the heart, argues at length in favor of the view that this organ alone is not equal to the task; and that other agencies, such as osmosis, capillary attraction, absorption, chemical affinity, etc., aid materially in the process.

To the physiological student the book is exceedingly interesting, not only for the novel views which it contains, but for the admirable way in which the author has presented the leading facts of his subject, as drawn from the whole range of living Nature. The print is good, and the illustrations, of which there are one hundred and fifty, are also well done.

disputes that have arisen in various quarters regarding the honor due to different investigators for working out the modern doctrines of "Energy" have been participated in by Prof. Tait, of Edinburgh, and this volume is probably due to his interest in the controversy. He was invited by a number of his friends to give a course of lectures on the chief advances made in natural philosophy since their student-days, and the author remarks that "the only special requests made to me were, that I should treat fully the modern history of energy, and that I should publish the lectures verbatim." The strictly historic part, however, is by no means the main, or the most important, feature of the work. It furnishes its method, but the book is valuable chiefly as explaining and expounding the modern doctrines of energy in a manner at once popular and thorough. No adequate exposition of these views has yet gained entrance into our text-books of physics; and a work was much needed, by a competent man, which would present the whole question in its latest aspects. The volume of Prof. Tait, though not without its defects, may be commended as meeting this want in a tolerably satisfactory manner.

thousand miles of travel affords large opportunity for observations, and to give an account of them in a book of three hundred pages seems a hopeless task. Mr. Vincent, however, has made the attempt in this racy book, and has succeeded fairly in presenting a series of descriptions of some of the more important places visited by him, and the reader follows him with interest to the close. His chapters on the Sandwich Islands, and on the journey to High Asia, to the sacred city of the Hindoos, and to the famous Taj Mahal, are especially full of interest.

sixth part of Dr. Bolton's "Notes on the Early Literature of Chemistry" treats of the ancient papyrus-book on medicine discovered by Ebers at Thebes, Egypt, two or three years ago. Dr. Bolton gives the table of contents of the book with some selected passages translated out of the hieratic original.