6o6 



NATURE 



[August 14, 19 13 



by the planets and the force of gravity at their sur- 

 faces, is therefore most useful. Mercury and the 

 outer planets are easily disposed of, and Mr. 

 Maunder even considers what would be the con- 

 dition of Jupiter and Saturn if cooled sufficiently 

 10 become solid at the surface. The results are 

 not encourag'ing. 



Special interest attaches to Mars, which is there- 

 fore discussed in considerable detail. The atmos- 

 phere is thinner than that at the top of the 

 Himalayas, and though the maximum tempera- 

 ture is well above the freezing point, water must 

 be normally in the state of ice and cannot be 

 liquid to a depth of more than one or two inches, 

 and that only in the torrid zone and during a few 

 hours each day. Mars is therefore essentially a 

 frozen planet, and the extremes of cold experienced 

 there, not only every year, but every day, far 

 transcend those of our polar regions. If there is 

 any vegetation it must be confined to some hardy 

 forms of a low type, stretches of which may 

 account for the so-called "seas." The polar 

 spots cannot be caused by snow, but only by 

 hoar frost. 



In a chapter on the illusions of Mars it is 

 shown that recent observations tend to resolve the 

 canals into disconnected knots of diffused 

 shadings. They are therefore caused by an im- 

 mense number of minute markings which, when 

 fairly near each other and separately below the 

 limit of distinct vision, appear like lines. Several 

 other illusions of Mars not alluded to by the 

 author were exposed by Johnstone Stoney in his 

 papers on telescopic vision in the Philosophical 

 Magazine in 1908. 



Venus is thus the only planet left which may 

 be inhabited ; but the question hinges altogether 

 on whether the rotation-period is something like 

 that of the earth, or equal to the period of revolu- 

 tion round the sun, which is still uncertain. In 

 the latter case one half of the planet will be 

 scorched and the other half frozen. 



OUR BOOKSHELF. 



Life in Ancient India in the Age of the Mantras. 



By P. T. Srinivas Iyengar. Pp. x+140. 



(Madras: Srinivasa Varadachari and Co. , 1912.) 

 This little book is a good example of the kind of 

 work which native Indian scholars are competent 

 to undertake. The author wisely leaves to Euro- 

 pean scholars the comparative study of ancient 

 Hindu beliefs and custom. He has undertaken 

 the more useful, if less ambitious, task of 

 analysing the Vedic Mantras, that is to say, the 

 older collection of hymns, as contrasted with the 

 Brahmanas or ritualistic treatises which supple- 

 ment them. He brings together in a systematic, 

 readable form the scattered references illustrating 

 no. 2285, VOL - 9 1 ] 



belief and custom. On the religious side he quotes 

 the original texts describing the priest and his 

 duties, magic, sacrifice, the fire cult, and the 

 state of the soul after death. In the social de- 

 partment he deals with the king and his nobles, 

 agriculture and other occupations, medicine and 

 surgery, household life, war, sea voyages, amuse- 

 ments, the status of women, and so on. In each 

 case he gives literal translations of the original 

 texts, either made by himself or collected from 

 authoritative versions, with detailed references 

 to the originals. The value of such a collection 

 is obvious, and the work, so far as it goes, has 

 been carefully and judiciously carried out. In 

 a new edition he would do well to replace the 

 extracts in Sanskrit, which is unintelligible to 

 most European anthropologists, by a Latin 

 version in those cases where it is impossible to 

 give an English rendering. 



Mr. Srinivas Iyengar proposes, with the help 

 of other scholars, to extend this series through 

 the later periods of Indian history. If these 

 monographs are prepared as carefully as' that now 

 before us the series will be welcomed by European 

 students of Hindu beliefs and sociology. 

 Probleme der physiologischen und pathologischen 

 ('hemic. By Dr. Otto von Fiirth. 2 Band. 

 Stoffwechsellehre. Pp. xiv + 717. (Leipzig: 

 F. C. W. Vogel, 1913.) Price 23 marks. 

 The appearance of the second volume of Prof. v. 

 Fiirth's important book will be welcomed by all 

 who have profited by reading the first volume. The 

 total work is divided into fifty lectures, twenty-five 

 in each volume. They might just as well have 

 been called chapters, for no teacher could ever 

 give lectures of such portentous length. Those 

 before us treat of the large subject of metabolism, 

 both in health and disease. We therefore not 

 only find a description of the chemistry of nutri- 

 tion, secretion, gaseous exchanges, and so forth, 

 but large sections are devoted to the considera- 

 tion of such subjects as diabetes and fever. 



The book is fully worthy of its author's emin- 

 ence in this branch of knowledge, and abundant 

 references to literature occur on every page. The 

 information is admirably up-to-date, and the book 

 can be confidently recommended to advanced 

 students as authoritative and interesting. The 

 interest might have been increased by the insertion 

 of illustrations ; even the advanced student will 

 find it difficult, for instance, to grasp the mean- 

 ing of dissociation curves of haemoglobin unless 

 these are graphically represented. 



Prof. v. Fiirth is to be congratulated on the 

 completion of his ambitious task, and his readers 

 will wish it every success. W. D. H. 



Practical Management of Pure Yeast. The 

 Application and Examination of Brewery, Dis- 

 tillery, and Wine Yeasts. By Alfred Jorgensen. 

 Translated by R. Grew Second edition. Pp. 

 128. (London : The Brewing Trade Review, 

 1913.) Price 55. net. 

 The first edition of this book was reviewed in 

 Nature of November 5, 1903 (vol. lxiv., p. 4). 

 The present issue has been revised and greatly 



