August 4, 192 1] 



NATURE 



713 



conditions of hypnotic trance and in a specially 

 contrived darkened cabinet, she is said to exude, 

 chiefly from the natural orifices of her body, a 

 plastic, amorphous substance which assumes (as 

 Hamlet said of his father's ghost) a questionable 

 shape, usually a face or a hand. The shape is 

 three-dimensional, and the author of this book, 

 who has studied the case at first hand and under 

 his own conditions in his own laboratory, tells us 

 that he has himself touched it and even felt the 

 bones beneath its skin. The exuded substance, 

 notwithstanding- its assumption of this solid shape, 

 is invariably, and generally expeditiously, re-ab- 

 sorbed by the lady, and the suggestion is that it 

 could not be detached or amputated without 

 serious, if not fatal, injury to the lady. 



The theory expounded in this book is that these 

 two phenomena, the histolysis of the insect and 

 the materialisation of the lady, are fundamentally 

 and essentially identical, and the study of them 

 has led the author to formulate a new principle, 

 which he names dynamo-psychism. This, he 

 claims, is a scientific principle which finally solves 

 all the problems of life and evolution. As a philo- 

 sophy it has had, he tells us, its forerunners in 

 Schopenhauer's theory of will and in von Hart- 

 mann's theory of the unconscious; but the great 

 merit which is claimed for the new formulation 

 is its overcoming of the pessimism inherent in 

 those theories. H. W. C. 



(i) The Copernicus of Antiquity {Aristarchus of 

 Samos). By Sir Thomas Heath. (Pioneers of 

 Progress. Men of Science.) Pp. v + 59. 

 (London: S.P.C.K. ; New York: The Mac- 

 millan Co., 1920.) 2s. 6d. net. 

 (2) Kepler. By W. W. Bryant. (Pioneers of 

 Progress. Men of Science.) Pp. 62. (Lon- 

 don: S.P.C.K.; New York: The Macmillan 

 Co., 1920.) 25. 

 (i) The first of these two Uttle books is the work 

 of a master-hand. Sir Thomas Heath published 

 in 1913 a valuable edition of the only extant 

 writing of Aristarchus, preceded by an introduc- 

 tion of more than 300 pages, in which he gave a 

 critical history of Greek cosmology up to the time 

 of Aristarchus. In the present little book he also 

 begins by giving a rapid sketch of the various 

 systems of the world proposed by Greek philo- 

 sophers. The statements of ancient writers are 

 next quoted, proving beyond dispute that Aris- 

 tarchus reallv put forward the heliocentric 

 hvpothesis. We could have wished that it 

 had been shown in more detail how Aristarchus 

 may have been led to propose this wav of " saving 

 the phenomena." Lastly, there is an account of 

 the contents of the treatise of Aristarchus on the 

 sizes and distances of the sun and moon, which 

 is of considerable mathematical interest. 



(2) Mr. Bryant's account of Kepler's life and 

 work, though very readable, is not altogether 

 satisfactory. The description of how the first two 

 laws of Kepler were found is not clearly expressed 

 and is incorrect In many details. When allud- 

 NO. 2701, VOL. 107] 



ing to Kepler's ideas on gravity it should 

 have been pointed out that his force was tangential 

 to the orbit and not directed to the sun. Of the 

 work on the harmony of the world we are 

 told that ** the fifth book contains a great deal of 

 nonsense." That Kepler distinctly states that 

 the harmony is only a mathematical conception, 

 and that there is not really any music of the 

 spheres, is not mentioned. The portrait given as 

 a frontispiece is not of Kepler. 



Cocoa and Chocolate : Their Chemistry and Manu- 

 facture. By R. Whymper. Second edition, 

 revised and enlarged. Pp. xxi + 568 + xv 

 plates. (London: J. and A. Churchill, 1921.) 

 425. net. 

 The first edition of this book appeared in 1912, 

 and quickly estabHshed for itself a reputation 

 as a useful book of reference, especially in 

 connection with the problems of cocoa and choco- 

 late manufacture, as distinct from those of cacao 

 cultivation and preparation. The second edition 

 has been largely rewritten and brought up to 

 date — a considerable task in view of the impor- 

 tant changes which have taken place in cacao 

 production and chocolate manufacture since 1912. 

 The book is divided into three parts : (i) the 

 history, botany, and agriculture of cacao ; (2) the 

 manufacture of chocolates and cocoa powders ; 

 and (3) the chemistry of cacao and its products. 

 The few defects of the first edition were nearly 

 all in part i, and have been remedied, so that the 

 book is now a reasonably complete account of 

 the whole industry It is well produced, and is 

 provided with a good index and numerous care- 

 fully selected illustrations. Presenting, as it does, 

 a broad survey of the whole subject, it should be 

 particularly useful at the present time, when 

 chocolate manufacture, at any rate in this country, 

 is at a somewhat critical period in its history. 



Mathematical Papers for Admission into the Royal 

 Military Academy and the Royal Military Col- 

 lege and Papers in Elementary Engineering for 

 Naval Cadetships and Royal Air Force for the 

 Years 1911-1920. Edited by R. M. Milne. 

 (London: Macmillan and Co., Ltd., 1921.) 

 I05. 6d. 

 All the papers described in the title which have 

 been set during the last ten years are here col- 

 lected in a single convenient volume. The answers 

 to the questions, where necessary, have been pro- 

 vided by the editor at the end of the book. To 

 those who are engaged in preparing candidates 

 for Army examinations this publication will be 

 extremely useful. 



Scurvy : Past and Present. By Prof. Alfred F. 

 Hess. Pp. vli + 279. (Philadelphia and Lon- 

 don: J. B. Lippincott Co., 1920.) 18s. net. 



Prof. Hess gives in this work the results of an 

 exhaustive study of scurvy in all its aspects — its 

 history, pathology, causation, symptomatology, 

 diagnosis, and treatment. The bibliography is 

 most complete. The work is very convincing. 



