OUR BOOK SHELF

Text Book of Botany.-- Lehrbuch der Botanik fur Gymnasien, Realschulen, &c. By Dr. Otto W. Thomé. 1 vol. 8vo. 358 pp., with 621 woodcuts. Price 3s. (Brunswick, 1869.)

DR. THOME'S name is new to us. He is a teacher in what we may call the Upper Grammar School at Cologne. Because he has not published original observations it does not follow that he should be a bad teacher. Rather, indeed, this is a point in his favour; for original observers, unless they be men of wide grasp of mind, or of great experience, are apt to ride special hobbies too far, and to be very unfair and crotchety.

A cursory inspection of this book leaves a favourable impression. It is German, of course, and the first chapter is entitled Die Zelle ads Individuum, but so far as we can judge it is a handy book for a beginner, and if not all pure milk, it does not seem very badly diluted: much cream now-a-days it is hardly fair to look for. It is very copiously illustrated; the cuts by no means all original, and not a few borrowed from this side the Channel, but none the less well adapted to their purpose. D. O.

The Retardation of the Beat of the Heart. -- Das Hemmungsnervensystem des Herzens. By Adolf Bernhard Meyer. (Berlin, 1869. London: Williams and Norgate.)

A CRITICAL and experimental inquiry into the inhibitory action of the pneumogastric nerve on the beat of the heart. The chief features of the experimental investigation are -- first, the extension of the facts of inhibition to many animals (chiefly reptiles) not hitherto specially examined in reference to this point. Curiously enough, in Emys lutaria the left pneumogastric is inert; unfortunately Dr. Meyer has not worked out the cause of this singularity. Second, the author brings experiments to show that the effect of stiumulation on the pneumogastric may be kept up for a very long time -- more than an hour. In frogs the effect may be carried as far as complete stoppage for this time; in mammals as far as retardation only of the beat. M. F

Exotic Lepidoptera.--Lepidoptera Exotica; or, Descriptions and Illustrations of Exotic Lepidoptera. By A. G. Butter, F.L.S., &c. (London: E. W. Janson.)

MR. BUTLER, who is well known as an ardent and careful student of the diurnal Lepidoptera, has undertaken, in conjection with Mr. Janson as publisher, what will no doubt prove a very valuable and beautiful work. Many new species of Lepidoptera have been described -- by Mr. Butler himself amongst others -- without any figure: this practice is exceedingly inconvenient to those who attempt to idenfiy species; and though, as Mr. Butler observes, it enables those who adopt it to ''call the beautiful their own" to a larger extent than if they had to wait for figures, it is nevertheless a reprehensible proceeding, and has afflicted the conscience of one at least who has been guilty of it. Mr. Butler is a very skilful artist, and evidently an intense admirer of the lovely colours and forms of the insects he deals with. Consequently it is a matter for congratulation that he has undertaken to make up for the shortcomings of past times, and intends to bring out once a quarter a part of his ''Lepidoptera Exotica,'' with three coloured plates of new or unfigured species. In the two parts already issued, which are before us, the figures are admirably done, and very handsome; whilst the descriptive text is concise, and in Latin in part. Some of Mr. Wallace's Bornean butterflies are figured in the second part. E.R.L.

Physiology of the Human Voice. -- Physiologie and Pathologie der Menschlichen Stimme. By Dr. M. J. Rossbach. (Wurzburg. London: Williams & Norgate.)

A TREATISE on the physiology of the voice, intended by the author to be useful not only to physiologists and pathologists, but also to those engaged in singing or in teaching singing. A chapter on the nature and qualities of sounds, based on Helmholtz' well-known work, and a short one on musical instruments, introduce the main topic, the physiology of the human organ of voice. There are also separate chapters on the vocal register, the different kinds of voice, and the relations of voice, speech, and song.

The Convolutions of the Brain.-- Die Hirnwindungen des Menschen. by Alex. Ecker, Professor of Anatomy in the University of Freiburg. (Brunswick, 1869. London: Williams and Norgate.)

A SUCCINCT but detailed description of the various Convolutions of the Brain, intended chiefly for the use of physicians. It is illustrated by half-a-dozen outline sketches. The references to the development of the convolutions are not very full, but the author promises a more complete account elsewhere.

The Absolute Value of Knowledge. -- Der Sebstandige Werth des Wissens. By Prof. K. Rokitansky. (London: Williams and Norgate.)

THE Materialist school of philosophy are just now getting very badly treated by men of science, much to the astonishment, it appears of the general public. Mr. Huxley has startled the world by proclaiming himself in a way a disciple of Berkeley and Kant, and here is Rokitansky, the great master of modern pathological anatomy, walking in a similar path. to many minds pathological anatomy would seem to be intensely materialistic. It is not so, however, to the Viennese professor. This little lecture is chiefly devoted to a development of idealism: of that kind of idealism, moreover, which ''makes the objective wholly and in every way dependent on the subjective, for the former is but the projection of the latter."

Tables of Pomona.-- Tafeln der Pomona, mit Berucksichtigung der Storungen durch Jupiter, Saturn, und Mars. By Dr. Otto Lesser. Publication der Astronomischen Gessellschaft. (Leipzig: Engelmann.)

THESE tables of Pomona are founded on the disturbance of the planets Jupiter, Saturn, and Mars, calculated according to Hansen's method, and published by the author in Nos 1596-7 of the Astronomische Nachrichten. The preface gives a full account of the character of the tables, illustrated in the usual manner by the calculation of the place of the planet Pomona for a given time.

Although it might seem that the construction of a series of tables as full and as elaborate as Bouvard's Tables of Jupiter and Saturn, would be a waste of labour in the case of a minute planet like Pomona, not merely invisible to the naked eye, but not appreciably affecting by its influence any of the great planets of our scheme, yet this is not in reality the case. Though Pomona cannot affect the other planets, yet these affect Pomona. Her sister orb, Thesis, has lately been made the means of affording a useful estimate of Juptier's mass, through the careful consideration of the perturbations which that planet exerts upon the tiny asteroid. Long since Nicolai applied the perturbations of Juno, Encke those of Vesta, Gauss those of Pallas, and Brunnon those of Iris, to the same end. The more such researches are multiplied, the more exact will be our estimate of the mass of the principal planets of the solar system. Therefore, the present tables, by means of which it will be rendered an easy matter to estimate the disturbing action of Jupiter, will have a high value. In a less exact but not unsatisfactory manner, the mass of Mars may be estimated from the same tables, since in certain positions the disturbances of Pomona caused by Mars' attraction can be readily separated from those of Jupiter. R.A.P.