April 12, 1906] 



NA TURE 



555 



a great tendency to cardiac weakness owing to the 

 direct action of insufficient oxygen in the blood sup- 

 plying the muscular walls of the heart. 



This scanty and imperfect sketch may serve to show 

 the very extensive field which is covered by the physio- 

 logical work of the expedition, but, in addition, many 

 valuable observations were made upon the symptoms, 

 progress, and nature of mountain sickness. The cause 

 of this complaint is, according to the authors, the 

 deficiency of oxygen transport by the blood. The in- 

 dividual variations in the manifestation of the symp- 

 toms and the disappearance of the symptoms on 

 habituation are considered to be due to the relative 

 adequacy or inadequacy of the mechanisms by which 

 the organism endeavours to protect itself against this 

 oxygen deficiency. One such mechanism is the cir- 

 culation flow, and if this is unable to bear the strain 

 of increase, then nervous influences diminish the vas- 

 cular area of the digestive organs in order to supply, 

 so far as practicable, the higher nerve centres in the 

 brain; in consequence of this anaemia, an extensive 

 derangement of the digestive functions is produced 

 which shows itself in the sickness and other symptoms 

 that are the characteristic features of the trouble. 



In conclusion, attention must be directed once again 

 to the practical bearing of the Rothhorn experiments. 

 These deal with the effects produced by moderately 

 high altitudes, and to such altitudes thousands of men 

 and women go every year, whilst the numerous sana- 

 toria frequented by invalids are situated at these 

 elevations. Moderate altitudes of less than 8000 feet 

 appear, in consequence of the lessened atmospheric 

 pressure, to benefit the whole organism in the follow- 

 ing particulars. The tissue which produces the 

 oxygen carriers of the blood is stimulated into greater 

 activity, the oxidation of abnormal substances is in- 

 creased, the heart's action is augmented, the respira- 

 tory muscular mechanism is brought into more 

 energetic use, and, finally, that proteid assimilation 

 which is so directly related to cell growth and cell 

 restoration assumes the phase present in the young 

 and growing animal. In consequence of all these 

 changes, and particularly the last one, altitudes of 

 from 4000 to 7000 feet must exercise a most bene- 

 ficial and even rejuvenating influence. In the case 

 of many invalids the effect will be to arm the body 

 for its fight against such insidious foes as the tubercle 

 bacillus and to hasten recovery in all cases of con- 

 valescence from bodily or mental prostration. Only 

 those whose circulation is seriously impaired directly 

 or indirectly by organic disease are debarred from the 

 probability of such beneficial effects. 



Experience has revealed to many the profound truth 

 which is expressed in the beautiful and familiar 

 words, " I will lift up mine eyes unto the hills, from 

 whence cometh my help." In their monumental 

 work Prof. Zuntz and his colleagues present physio- 

 logical reasons for the assurance that whilst moun- 

 tain scenery may arouse the imagination, mountain 

 air will stimulate those organic functions which form 

 the foundation for health of body and happiness of 

 mind. F. G. 



NO. 1902, VOL. 7l\ 



A COMPREHENSIVE DYNAMICS FOR 

 PHYSICISTS. 

 The Dynamics of Particles and of Rigid, Elastic, and' 

 Fluid Bodies. By Prof. Arthur Gordon Webster.. 

 Pp. xii + 588. (Leipzig: B. G. Teubner, 1904.)' 

 Price 10 marks. 



ATTENTION has been directed in more than one 

 recent review to the tendency to over elabor- 

 ation in the standard treatises to which an English 

 reader would naturally turn for information on such 

 branches of applied mathematics as the principle of 

 least action, the potentials of ellipsoids, or the equa- 

 tions of motion of a perfect fluid. What has been 

 said already must be said again, in order to make 

 good the claims which Prof. Webster puts forward 

 in his preface, and to prove that this book, written 

 by an American and published in Germany, fills a 

 distinct want. 



That the student of physics should have to consult 

 five volumes of Routh, three of Love, and a large- 

 work of Lamb is a state of affairs which could not 

 very well be allowed to continue. It is true that 

 these treatises afford an excellent preparation for the 

 man who proposes to devote his whole lifetime to 

 mathematical research, regardless of cost. But it is 

 becoming more and more evident that the physicist 

 must know something about the intricate mathe- 

 matical machinery which has been so successfully 

 employed to bring a large proportion of physical 

 phenomena into one connected theory. We include 

 under this category reversible phenomena. Whether 

 the subject-matter of this book is called dynamics, or 

 the study of quadratic forms, or the theory of geo- 

 desies in a hyperspace with special reference to> 

 particular definite applications makes no difference. 

 The present reviewer may perhaps be allowed once 

 more to state his conviction that irreversible energy 

 transformations, whether statistical or non-statistical 

 in character, cannot satisfactorily be accounted for 

 as properties of quadratic forms except by the method 1 

 of energy-accelerations, that is, by studying the' 

 second, and not the first, differential coefficients with 

 respect to the time of the squares and products occur- 

 ring in the energy function. But the omission of 

 these phenomena leaves a great portion of modern 

 physics which cannot be properly understood without 

 some knowledge of a very extended and very advanced' 

 portion of applied mathematics. 



In his preface — which, by the way, is so exhaustive 

 as to leave a reviewer but little fresh to add — Prof. 

 Webster states of the book that " It is obvious that 

 it leads to no particular examinations, from which 

 we in America are to a large extent fortunately free."' 

 Examples, as such, are therefore omitted, although 

 most of the standard applications of general prin- 

 ciples are included in the text ; for instance, motion 

 of a spherical pendulum, the brachistochrone and 

 tautochrone under gravity, potentials of a disc and 

 cylinder, form of a rotating liquid in a uniform field 

 or under self-gravitation, torsion of elliptic and 

 triangular prisms, and so forth. In connection with 

 these applications an intentional feature is very con- 



