Page:Popular Science Monthly Volume 51.djvu/733

Rh upon bacteria in water, Prof. H. Marshall Ward would explain the comparative freedom of river waters under the blazing hot summer sun from bacteria as against the more abundant infection of the same waters in winter. Pasteur and Miquel found that the germs floating in the air are for the most part dead—killed, the author holds, like the germs in the air of the Alps, by the sun. Yeasts which normally vegetate on the exterior of ripening grapes are destroyed, according to Martinaud, if the heat be very intense; and Giunti has observed that the ingress of sunlight hinders acetic fermentation—a bacterial process. So the access of light appears to be inimical to the germination and develmentdevelopment [sic] of fungi of various kinds. The destructive rays may be cut off by color screens, and the protected germs can then sprout and develop as easily as if no light was playing upon them. Such color screens appear to the author to be common in Nature, where the spores and tender growing cells are compelled to begin their vegetative processes in the light. The green chlorophyll screen of ordinary plants may fulfill this purpose. When the typhoid bacillus falls into turbid, dirty water in summer, it finds a congenial propagating place. The dirt furnishes it food, absorbs heat to increase the warmth, and keeps off the hostile blue and violet rays.

The Appraisal of Books.—The subject of furnishing librarians and the public with some general, comprehensive guide to the character and real value of books is discussed by Mr. George Iles in a paper on The Appraisal of Literature, which he presented to the International Library Conference held in London in July. The task of selecting from the enormous mass of books now appearing daily to be bought or read is a bewildering one. How make it easier? Mr. lies would reach the end.by a system of shortened reviews, prepared and adjusted for the purpose—"a brief note of description, criticism, and comparison, written by an acknowledged authority, signed and dated, and placed where the reader can not help seeing it, both within the lid of the reviewed book itself and on a card next the title-card in the catalogue." If the book treats of a question in debate, fact and opinion should be carefully distinguished, and views of opposed critics might be presented. By this means the inquirer would know which book is best, or among the best of its kind; would be made aware of defects; would learn how one book can gainfully piece out another; and would gather indications of the periodicals or transactions which bring a story of discovery and research down to date. In a final line he might be told where detailed reviews are to be found. Persons qualified to undertake this business of appraisal might be found among professional reviewers, who could "boil down" their larger reviews and adapt them. The work might be placed under the direction of a central superintendency of the American Library Association; and in connection with it something might be done "to rescue from neglect the great books which, from such causes as the untimely death of their authors, or the sheer brunt of advertisement, are overlaid by new and much inferior writing." Starts have been made toward this work in such manuals as the Reader's Guide in Economic, Social, and Political Literature, the List of Books for Girls and Women and their Clubs, and the special lists of books on fine art and on music.

Man's Language to Animals.—The exclamations we use in driving and calling horses, oxen, cats, dogs, fowls, and other domestic animals are presented by Prof. H. C. Bolton in a paper on the subject as affording familiar illustrations of a language of peculiar characteristics, whose words are chiefly monosyllabic and dissyllabic, and usually repeated in groups of three, utterly devoid of grammar, exclusively in the imperative mood, and consisting of words not found in the dictionaries, which serves as a ready and sufficient means of communication between man and the many races of animals under his subjection. It has little in common with the language used by the animals themselves, but is forced upon them by man and made comprehensible to them by constant repetition. The terms used are different in different countries. In thus controlling the actions of domestic animals by the voice, man makes comparatively little use of the language by which he communicates with his fellow-creatures, but employs a