Page:Popular Science Monthly Volume 37.djvu/288

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mind acts first upon body, or body upon mind. This M. Ribot declines to discuss. Voluntary attention originated after the earliest period of savagery, when man realized the alternative of perishing or going to work. It differs from the spontaneous form in that the motive or influence producing the emotional state is supplied from without. Educators make use of fear, sympathy, and curiosity, to cultivate attention in the child; as it advances in growth, duty, emulation, and ambition are introduced; and, finally, voluntary attention is maintained by habit and organization A study of the internal mechanism shows that attention is accomplished by inhibition. In the normal state of consciousness, sensations, images, ideas come and go. Attention arrests this process and inhibits all but the chosen series. Energy is used to perpetuate this condition, and from this expenditure results the feeling of effort. The morbid cases of attention are treated under the heads Hypertrophy of Attention, Atrophy of Attention, and Congenital Infirmity. They prove that attention depends upon emotional excitation. Incidentally, M. Ribot gives some suggestive examples of what may depend upon full recognition of the physical nature of attention.

The Extermination of the American Bison. By William T. Hornaday. Washington: Government Printing-Office (Smithsonian Institution). Pp. 548, with Plates and Maps.

Mr. Tornaday is a naturalist and taxidermist by profession, and is superintendent of the National Zoölogical Park, thus combining qualifications which well fit him for making a book of this kind. He is, furthermore, a writer who knows how to interest the reader, and has composed an attractive as well as an instructive book. His purpose is to help the public fully to realize the folly of allowing all our most valuable and interesting American mammals to be wantonly destroyed, as the buffalo has been. The wild buffalo is practically gone forever; and it is doubtful whether the institution of preserves and the formation of herds, however intelligently they may be executed, will avail to save the species permanently, even in a captive state. In the first part of his work the author considers "the life-history of the bison," under the headings of Discovery of the Species, Geographical Distribution, Abundance, Character, Habits, Food, Mental Capacity and Disposition, Value to Mankind, and Economic Value to Western Cattle-Growers. The story of extermination is related in the second part. One of the most important chapters in the first part is that in which the value of the bison is estimated under domestication, in hybrids, and as a beast of burden. At present (May 1, 1889), "although the existence of a few widely scattered individuals enables us to say that the bison is not yet absolutely extinct in a wild state, there is no reason to hope that a single wild and unprotected individual will remain alive ten years hence. The nearer the species approaches to complete extermination, the more eagerly are the wretched fugitives pursued to the death wherever found." While the herds, which once ranged over nearly the whole of our country, formerly numbered hundreds of thousands of individuals, the few groups that are left count only dozens. An estimate made on the 1st of January, 1889, gave the whole number running wild—in all North America—as 635; and including those in captivity and those under Government protection in Yellowstone Park, the whole number of individuals of the species as 1,091; and these few are still hunted, and shot when found.

Handbook of Practical Botany. By E. Strasburger. Edited from the German by W. Hillhouse. Second edition, revised and enlarged. New York: Macmillan & Co. Pp. 425. Price, $2.50.

This volume embodies a course of laboratory work laid out by a botanist whom the English editor calls "one of the greatest living masters of microscopical observation." The introduction tells how to use the microscope, and describes the instruments of different makers. The first subject for study is the structure of starch of different kinds. A list of the material wanted is given at the head of the chapter; the appearance which each kind of starch should present under the microscope is described, its behavior under various reagents is noted, and directions for drawing the grains are given. The following lessons are similar in character. Among the subjects for investigation are movements of protoplasm, epidermis and stomata, the