Page:Popular Science Monthly Volume 9.djvu/267

Rh papers will be found chiefly in the first two volumes; descriptions of improved methods of warming and cooking occupy the third; and the greater part of the last is devoted to philanthropic essays; but this also contains the scientific papers on light. The volumes are splendidly illustrated and elegantly printed. The American Academy of Sciences could have given no worthier tribute to the fame of this man than to furnish the world with so excellent an edition of his writings.

work is intended to present more fully than has been done before the habits, food, migrations, and other characteristics of the birds of Eastern Pennsylvania.

Especial attention is given to the building of nests; showing wherein they vary, and the causes for such variations.

The labor of nidification; the periods of incubation, and the part which the male takes in it; the age when the young quit their nests; the character of the sexes before and after incubation; and the food, as insects, seeds, and berries, on which the birds, old and young, depend, are carefully considered by the patient and indefatigable author.

Very much of value is thus added to our knowledge of bird-life, and what is specially important to our knowledge of the instincts and mental constitution and emotions of birds.

We look for good results from the labors of Mr. Gentry. The system of classification he adopts is the same as that of Dr. Elliott Coues in his "Key to North American Birds."

an account of all changes and additions in the various sections of the Museum during 1875. From the report on instruction in zoölogy, it appears that during the year 1874-'75 there were eighteen students attending the lectures of Prof. McCrady. A detailed statement is made of the condition of the Agassiz Memorial Fund.

this work we have what the Lancet justly calls "the first serious attempt at a great generalization on an avowedly difficult subject." The author has undertaken no less a task than to show that the circulation, as it takes place in plants, animals, and man, is essentially the same in kind; differing mainly in the degree of complexity attained by the organs which carry it on, and of the resulting movements of the circulating fluids.

The book opens with a brief history of the growth of the subject, from the fanciful notions held centuries ago by the Chinese that "the circulation of the vital heat and radical humors commenced at three o'clock in the morning, reached the lungs in the course of the day, and terminated in the liver at the end of twenty-four hours," up to the exact scientific demonstrations of Harvey and Malpighi. "The term 'circulation,' in the present day," says the author, "is employed in a double sense. In its wider signification it embraces the course of the nutritious juices through plants and the lower order of animals; in its more limited signification, and as applied to man and the higher orders of animated beings, it indicates the course of the blood from the heart to the capillaries, and from these back again to the heart. The word 'circulation' literally means a flowing round, a going and returning; and it is well to bear the original meaning in mind, as we shall find that a single circle aptly represents the circulation in most of the lower animals, a circle with one or more accessory loops, representing the circulation in the higher ones."

The circulation in plants is first described, the ascent, descent, and lateral distribution of the sap, and the forces which maintain the flow, being each fully treated. Many curious resemblances between the circulation in plants and that in animals are pointed out in this section of the work. On this point the author says: "I now proceed to a consideration of the circulation as it exists in animals; and an attentive examination of the subject not only induces me to believe that there is a striking analogy