Page:Popular Science Monthly Volume 42.djvu/727

Rh, and the various reactions are explained. The section describing peptones now includes albumoses, that are classed with the former, both on account of their close relationship and for convenience. The author calls attention to the fact that various substances that have been described as peptones have consisted, to an extent at least, of a mixture of true peptones with variable quantities of albumoses, and that our knowledge of true peptones is at present in a state of transition. In fact, as he truly states, until some new property of proteids is discovered by which their absolute purity may be determined, the question of the constitution of proteids will probably remain unsolved.

A new section is added on the enzymes, in which we find descriptions of trypsinogen, pialyn, rennin, muscle-enzyme, and ureaenzyme.

In the section on the nitrogenous non-crystalline bodies allied to proteids, descriptions of the mucin of bile, of that of the submaxillary gland, and of that of the umbilical cord, of gelatin-peptones, of neurokeratin, of chitin, and of nucleo-albumins have been added. In the section on carbohydrates the dextrins are now well described; while the sugars are satisfactorily explained by Emil Fischer's able researches regarding the several members of this class of carbohydrates.

In the sections on the fatty acids and fats, on the amides and amido-acids, on urea and the uric-acid group, on the bile acids, and on the coloring matters and pigments of the animal body, much recent material has been incorporated, while a brief section is devoted to ptomaines and leucomaines.

The volume is a most useful addition to the literature of the subject; the numerous references it contains will permit the student to consult original authorities should he so desire; while in general an immense amount of time will be saved for those studying this subject by this collocation of results that are scattered throughout medical literature.

An admirable idea is embodied in the series of English Classics for Schools of the American Book Company—a series in which the masterpieces of English literature are presented in attractive form for reading in class or for supplementary reading. Of this series there are now sent to us Ten Selections from the Sketch Book of Washington Irving, Shakespeare's Tragedy of Julius Caesar, and his Comedy of Twelfth Night, at the price of twenty cents each, and Sir Walter Scott's Ivanhoe at fifty cents. With the text are given brief notices of the author, with analyses of the particular works.

attention having been directed to the individuality and significance of the marks made by the tips of the fingers, he was surprised when he came to inquire into the subject at perceiving what had been done, and what a promising field of inquiry still lay in it. He found it of real importance and investigated it, with results, truly curious and valuable, which are given in this book. The account begins with notices of the previous employment of finger prints among various nations, with objects partly superstitious and partly ceremonial; then various methods of making good prints are described at length; next, the character and purpose of the ridges, whose lineations appear in the finger prints, are discussed. These preliminary topics having been disposed of, the inquiry proper begins with a discussion of the various patterns formed by the lineations, illustrated by plates of the principal varieties. The question is raised as to the persistence of the patterns, or whether or no they are so durable as to afford a sure basis for identification, and is answered, except as to proportions, in the affirmative. An attempt is made to appraise the evidential value of finger prints by the common laws of probability. A succeeding chapter deals with the frequency with which the several kinds of patterns appear on the different digits of the same person; and in it unexpected relationships and distinctions are established between different fingers and the two hands. Methods of indexing are discussed and proposed, by which a set of finger prints may be so described that it may easily be searched for and found in any large collection. The practical results of the inquiry are discussed as to its possible