Page:Popular Science Monthly Volume 36.djvu/873

Rh are especially associated with the mental activity of town-dwellers. Their children are sickly, and if it were not for the constant inflow of new blood from the country, the towns would be depopulated in three or four generations. Dr. Richardson, in his introduction to the volume, says, "The divisions are excellent, the title of each division attractive, and the mode of progress from stage to stage artistic." He draws attention to certain "short, sharp sayings, each one in its proper place, and easily learned and not easily forgotten." As samples of these he quotes, "Flags and pavements produce no grass." "Brains are the finest raw material of a country." "To kill the weak and injure the middling is a long price for education." He calls it also an eminently suggestive book, which, if the author had lived, would doubtless have been expanded.

author offers this production as an essay toward a theory of the formation of the earth's crust. In his discussion he makes liberal use of passages in the writings of the leading geologists, which often reveal wide differences of opinion concerning the questions discussed. He also puts at the heads of several chapters, and scatters through his text, passages from the Bible, with which he evidently deems it essential that his views should conform. A striking case of this tendency to subordinate his opinions to the imagined geological teachings of the Bible is where he says that the earthquakes which now occur result from disturbance of the crust in one or other of the old lines of rupture, and asks, "Who can earnestly consider this condition of the earth and say that it may not be nearly ripe for another paroxysm?" He then quotes from Prof. Hitchcock to the effect that the earth contains within itself chemical energies sufficient to accomplish its own destruction, and adds, "We have the yet older and surer revelation that the earth shall reel to and fro like a drunken man, and, when enveloped in flames, all the works of man shall be burned up." This, in spite of the fact that the progressive cooling of the earth points to its end in frigidity.

plan of this important work is new. It adopts the comparative method, begins with general biology, treats of the cell as the unit, gives an account of unicellular vegetal organisms both on the morphological and the physiological side, then of unicellular animals, next of multicellular organisms, leading up to a consideration of the animal body, the animal kingdom and man's place therein. Following all this is a full exposition of the origin of life in general and of reproduction, very admirably presented. Then the chemical constitution of the animal body is taken up, the blood and the contractile tissues are examined, the graphic method is extensively applied to the study of muscle physiology, the circulatory system is explained, succeeded by an account of the digestive system. Excretion is next dealt with, then the metabolic or chemically transforming processes, while the nervous system and the senses form the concluding portions of the work.

The plan has obvious advantages. It is much better adapted to giving the learner a correct and comprehensive view of physiology than treatises in the usual form and order. Moreover, the work in question is admirably executed and has all the characteristics of a truly scientific production. It is certain that physiology must be hereafter studied with reference to general biological laws, and not by piecemeal methods. Then books like the present one will inevitably supersede the older text-books, presenting a less unified physiology. Dr. Mills's volume will help this progress. It may be safely recommended as one of the best treatises on the subject extant, and in respect to method we know of none more praiseworthy.

has given us a handy and useful book, comprehensive and practical. The