44 



NATURE 



[March 15, 19 17 



The book will ao ^ood if it rouses any reader 

 from the torpor of an easy orthodoxy. It may 

 excite doubts, if it cannot allay them. The lan- 

 guage and printing of the book make it something 

 of a curiosity. Cosmopol-tanism is a virtue we 

 are glad to meet in these days. Still, English 

 d la Hollandaisc is a sore distraction in a serious 

 book. W. Bateson, 



OUR BOOKSHELF. 

 The Biology of Tumours. By C. Mansell Moullin. 



Pp- 55- (London: H. K. Lewis and Co., Ltd., 



1916.) Price 2s. 6d. net. 

 This book comprises the Bradshaw Lecture, 

 somewhat extended, delivered by Mr. Mansell 

 Moullin before the Royal College of Surgeons in 

 1912. The author admits that the conclusions he 

 has arrived at differ in many particulars from the 

 views that are generally current ; nevertheless, his 

 suggestions are stimulating, and in the present 

 state of our knowledge of the causation of tumours 

 it cannot be said that they are erroneous. Mr. 

 Moullin divides tumours by their mode of origin 

 into two classes : one due to the sudden awakening 

 of the innate reproductive power of the tissues, in 

 virtue of which they give birth to " buds " that 

 grow into tumours; the other due to details of 

 structure not being carried out so completely as 

 they ought to be. The distinguishing feature of 

 the former class of tumours is their independence : 

 they grow quite irrespective of the tissue in which 

 they develop. This group includes the vast 

 majority' of tumours, innocent and malignant. De- 

 velopment is the influence which restrains the 

 potentiality possessed by the cells of the tissues 

 to multiply indefinitely, and is due to chemical 

 influences. All that is needed, then, for tumour 

 formation is some exciting cause, mechanical or 

 chemical, to give the growth a start. Thus, mul- 

 tiple tumours of the skin may develop from the 

 prolonged administration of arsenic, tumours of 

 the bladder are relatively common in workers in 

 fuchsin, and cancer of the skin often follows the 

 continued application of soot, tar, and paraffin. 



We believe we have stated the author's views 

 correctly, though they are somewhat difficult to 

 follow, and it would have been useful had he given 

 a brief summary at the end of the book. In some 

 respects the hypothesis is similar to that of Ross, 

 who regards certain chemical substances — 

 'Vauxetics," as he terms them — as capable of in- 

 ducing cellular proliferation. 



Atoms. By Prof. Jean Perrin. Authorised 



translation by D. LL Hammick. Pp. xv + 211. 



(London: Constable and Co., Ltd., 1916.) 

 Price 6s. net. 



The appearance of the authorised translation of 

 Prof. Perrin's book, '* Les Atomes," is very wel- 

 come. It is true that the demand for translations 

 into English of ordinary French scientific works is 

 not great, but books of the semi-popular kind 

 such as the one under review are in a rather 

 different category. A student with only a 

 NO. 2472, VOL. 99] 



moderate knowledge of French may read with 

 advantage a standard French treatise, but he 

 would be apt to miss the point of many of the 

 illuminating illustrations and analogies with 

 which Prof. Perrin's work abounds. 



Mr. Hammick is to be congratulated upon the 

 excellence of his translation. Without previous 

 knowledge, one would scarcely suspect that the 

 book is a translation at all — it reads as though 

 it had been written in English in the first instance. 

 And yet, upon comparison with the original, it is 

 found that the translator has adhered remark- 

 ably closely to the text. A few small errors have 

 survived revision — for example, the use of 

 definitely for definite on p. x, line 26, and which 

 for who on p. 207, line 37. 



The original French edition has been already 

 reviewed. In the present translation there is an 

 additional paragraph dealing with Mr, C. T. R. 

 Wilson's beautiful photographs of the paths of a 

 and j8 particles. The book is well bound and 

 printed, and is unhesitatingly recommended both 

 to those who will appreciate a popular exposition 

 of the subject, and to those to whom it is of in- 

 terest to survey the modern methods and results 

 in widely differing fields of research converging 

 towards the same end. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected ■ manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



Thermodynamics and Gravitation. 



The Carnot cycle in Dr. G. W. Todd's interesting 

 letter (Nature, March i, p. 5) leads by a ready ex- 

 tension to the result that if the force of gravitation 

 on a body depended on its temperature, and thermo- 

 dynamics were applicable, there must be interaction 

 between the gravitational field sustained by a body 

 and its thermal molecular energy ; so that part of 

 the exhaustion of energy of position when the field 

 does work on the body would go to increase its 

 store of heat, only the remainder appearing as work 

 done. Thus when, owing to displacement of a body 

 of mass m in the field of force, work 8W is done 

 against the field, so that energy 8W is gained, then 

 also heat must be gained bv the bodv of amount 



- - i^ SW, if its temperature is not to chang'e. 



There would bo dissipation of energy involved in 

 the diffusion of such heat, just as in the case of 

 heat of compression in sound-waves of very slow 

 period. Only in two ideal limiting cases will 

 there be conservation, and then 8W will be the 

 increment, arising from the displacement alone, of 

 a function of position and also temperature, which 

 thus constitutes a gravitational potential W : in these 

 cases the heat of the body will depend definitely on 

 its temperature T and its position in the field of 

 force, the latter contributing an amount constant 



. These two cases, of some curious theoretical 



7/1 aT 

 interest, are ; (i) that of a universe isolated in an 

 enclosure maintained isothermal bv internal radia- 



