Page:Popular Science Monthly Volume 24.djvu/584

568 more or less magnified, and is to be distinguished from micro photography, which merely takes microscopic photographs of objects that can be seen by the naked eye. The former art is scientifically instructive, the latter merely produces curiosities. The author's object in preparing the volume has been to give such an account of the technique of the art as will enable persons familiar with the use of the microscope to make photo-micrographs of suitable objects with a minimum expenditure of time and money. The illustrations have been selected with a view of showing the kinds of microscopic objects best suited for photographing, and the results which may be expected by one who is willing to devote a little time to the mastering of technical difficulties. They represent forty-nine different objects.

undertakes to controvert the sewer-gas theory of the origin of typhoid fever, by showing that the disease is not dependent upon the presence or absence of sewers, or upon any conditions of filth in large cities; and that it prevails in the country, where there are no sewers, and everything is favorable to purity of the atmosphere, more extensively and more fatally than anywhere else. Dr. Ayer maintains substantially the same points, but rather on philosophical grounds than by the citation of examples, and disputes the competency of the experiments which have been relied upon to determine that bacteria are the cause of the diseases with which they have been found associated.

paper is an inquiry into the cause of the persistency of the influence of Greek art upon us. The answer is found in the fact that Greek art is true to nature, yet not so servile as to be sensual and sensational, but is also ideal. "The ideal in art is the highest generalization of form. In Greek art it was the highest generalization of the forms of nature. The works of Greek art are, therefore, not dependent for appreciation upon one individual spectator, or one special mood of the individual, but are valid for all sane men, for all men of a certain physiological constitution of their senses, surrounded by man and nature relatively the same." The inquiry is pursued how Greek art effected this combination of the natural and the ideal. The natural was developed in the portraiture of athletes, the ideal in the effort to represent and characterize the gods.

is No. 13 of the "Q. P. Index," a series of works for the projection and execution of which Mr. Griswold, who has made it his special business, deserves the thanks of every student and reader. The character of the present number of the series is fairly well represented by its title. There are hosts of articles of great value on particular subjects inclosed in volumes of essays and miscellaneous writings, which are practically inaccessible because the general title of the volume gives no clew to what is in it. The present index gives the key to the subjects within its scope as represented in 799 volumes by different authors. The publisher hopes in time to improve upon it and enlarge it that is, to bring other books into view.

to young men on the importance of personal purity and of the restraint of all tendencies to vicious indulgence, the destructive physical and moral consequences of which are pointed out in language that does not err by lack of plainness or vigor. As counteractives to vicious propensities, are recommended cold bathing, hard beds, and sleeping alone, abundant work, plain food, careful reading, right choice of companions, and religion.