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710 view of it might be expressed as follows: If all the physical forces are but affections of matter, quivering particles of the medium affected, it is easy to see that the senses, which we find to be special adjustments of ourselves to these different forces, are merely channels of different kinds of motion leading to the brain. In a word, therefore, the sensation of light is a definite motion of a definite part of the brain. If it were possible to study the lines or areas of motion which a sensation of a given intensity sets up in the brain, or the structural changes which accompany the repetition and combining of different sensations, there would be some hope that the physical or subjective aspect of the law of association could be explained. The difference between the apprehensions of this law by Hartley and Mill is that Hartley, being a physiologist, and moved by the excitement of discovery, endeavored to portray the subjective aspect of this law, while Mill devoted himself to its manifestations in the relations and history of life.

The author has made a great many selections from these two writers, which has the effect of bringing their systems into view side by side. He precedes these selections with a biographical sketch of Hartley and Mill, and accompanies them with comparisons and criticisms of his own, which constitute the greater part of the book. The value of such a book depends, of course, upon the point of view from which the criticisms are made, and the skill of the selections. With regard to the latter, but little improvement could be suggested, and, although some opportunities have been neglected of bringing important points into bold relief, the criticisms are remarkably just and free from error.

author of this book has added another to the already considerable list of useful little manuals on practical chemistry. He confines himself to organic chemistry and has endeavored to make the study of that branch of science more interesting to the quite elementary student than has been done by previous authors. The work is not a text-book, but merely a laboratory companion for the student, and is, moreover, especially arranged for those who have but a limited time at their command. It is not illustrated, though a good number of simple experiments are described.

is precisely what its name implies. The contents are arranged under the general headings of Herborizing, Field-Work, Collecting and preserving Fungi, Closet Work, The Herbarium, Bibliography, Herbaria, and Public Herbaria.

Under each of these headings much valuable information for the collector is given.

The Epidermal Organs of Plant?: Their Morphology and Physiology. By Charles F. Cox, F. R. M. S. Pp. 15.

A Report on the Teaching of Chemistry and Physics in the United States. By Frank Wigglesworth Clarke, S. B., United States Bureau of Education. Pp. 219.

"The Tonic Sol-Fa Advocate." Edited by Theodore F. Seward. Vol. I, No. 1. New York: Biglow & Main. Monthly. Pp. 16. 50 cts. a year.

Annual Report of the Board of Directors of the Chicago Astronomical Society, together with the Report of the Director of Dearhorn Observatory. 1881. Pp. 16.

Descriptions of some New Tortricidæ (Leafrollers). By C. V. Riley, M. A., Ph. h. Washington. Pp. 9.

Some Double and Triple Oxalates containing Chromium. By F. W. Clarke. The Titration of Tartaric, Malic, and Citric Acids, with Potassium Permanganate. Preliminary Note. By F. W. Clarke. Pp. 7.

Pliocene Man in America. By James C. Southall, A. M., LL. D.. of Richmond, Virginia. New York: A. D. F. Randolph & Co. Pp. 30.

Braithwaite's Retrospect of Practical Medicine and Surgery. Part lxxxiii. New York: W. A. Townsend. Pp. 276.

What shall We do with the Inebriate? By T. D. Crothers, M. D. Hartford, Connecticut. Pp. 24.

Hip-Injuries, including Hip-Joint Disease, and Fractures of the Femoral Neck: Splint for. By De F. Willard, M. D. Philadelphia. Pp. 4.

Hip-Joint Disease; Death in Early Stage from Tubercular Meningitis. By De Forest Willard, M. D. Microscopic Appearances, with Cuts. By E. O Shakespeare, M. D. Cambridge: Riverside Press. Pp. 20.

Fifth Annual Report of the State Board of Health of Wisconsin. 1881. Madison, Wisconsin. Pp. 156.

Catalogue of the Phænogamous and Vascular Cryptogamous Plants of Michigan, Indigenous, Naturalized, and Adventive. By Charles