Page:Popular Science Monthly Volume 48.djvu/141

Rh and the same phenomena of reproduction. As the beginning of the plants and of the study of them we are told of the living principle in them, represented by the protoplasts, which are considered as the seat of life, and of their movements, secretions, and constructive activity, and their communication with one another and with the outer world. The next steps are the absorption of nutriment from inorganic substances and organic and the changes it produces in the soil; the conduction of food; and the formation of organic matter from the absorbed inorganic food, with the functions of chlorophyll and the green leaves. Metabolism and the transport of materials are considered with reference to the organic compounds in plants, the transport of substances in living plants, and the propelling forces in the conversion and distribution of materials. Under the heading of the Growth and Construction of Plants are included the Theory of Growth, Growth and Heat, and the Ultimate Structure of Plants. The last chapter of the present volume relates to plant forms as completed structures, and in it are discussed the progressive stages in complexity of structure from unicellular plants to plant bodies and the forms of leaf, stem, and root structures. The volume concludes with the observation that the just pride and satisfaction we may have in what we have gained in the knowledge of plants "must not blind us to the recognition of the fact that most questions concerning the life of plants are as yet only at the commencement of their solution." The work is illustrated by about one thousand original wood-cuts and sixteen plates in oil colors.

Menschutkin's Analytical Chemistry -is a college manual embracing both qualitative and quantitative analysis. Its most distinctive feature is the care that the author has taken to make the student understand the reasons for what he is doing. In the qualitative determination of metals the corresponding compounds of all the metals of a group are studied, and the conditions necessary for the separation of one group from another are deduced (General Reactions), after which the behavior of the compounds relied upon for detecting single metals (Special Reactions) is considered. A systematic course of analysis for the group in hand follows. With the metalloids, on the contrary, the special reactions of these elements and their compounds are first considered, and the student then passes to the complicated methods required for detecting the elements when occurring together. In the quantitative part the chief methods of gravimetric and volumetric analysis and the analysis of organic compounds are set forth. Here the author has followed also, so far as practicable, the procedure employed in the qualitative part.

It is generally accepted now that all life originated in the sea, and very probably in the littoral or coast region. The constantly varying conditions here, due to the surf and the tides, doubtless had a large share in determining form and structure; the violence of the surf beating its inhabitants to death, and the retreat of the tide exposing them to the attacks of predatory birds and beasts and to new atmospheric conditions. Hence in all probability have originated the various forms of adaptation which are calculated to bring about the survival of the fittest. The widespread effect of these factors in shaping present forms lends a special interest to the study of the littoral life of to-day. The general plan of classification in the work before us is not that of any single authority. The authors have adopted the views of the leading specialists in the various groups. While this has the advantage of placing before the student the results of recent investigation, it occasions a certain number of discrepancies where the departments overlap, which are likely to lead to confusion. Up to recent times the mollusca have been regarded as one of the four subdivisions of the great family Malacozoa. The progress of investigation, however, tends to the belief that the mollusca are not so closely related to these groups as such a classification implies. The authors think that any attempt definitely to relate them to one group or another is to go