2IO 



NATURE 



[October 14, 1920 



of the long-period variables of large light-range, 

 since visual estimates of light-difference are suffi- 

 cient in these, while the Cepheids and eclipse- 

 variables call for more refined methods and more 

 highly trained observers. The use of charts for 

 identifying the variable and comparison stars is 

 explained, also the "fraction" and "step" 

 methods of estimating light-intervals, the draw- 

 ing of the light-curve, and the deduction of 

 the epochs of maximum and minimum. The 

 amateur who contemplates extensive work in this 

 field is wisely recommended to join the variable 

 star section of the British Astronomical Associa- 

 tion ; its director makes a selection of the stars 

 needing observation, and divides the work among 

 its members. 



The physical explanation of variation lies out- 

 side the scope of the little book, but something 

 is said about the resemblance between light-curves 

 and the curve of sun-spot activity. 



It may be noted that the author, though he 

 writes in French, has been resident in England for 

 many years, and is a lecturer at the Woolwich 

 Polytechnic. 



A/JIttary Psychiatry in Peace and War. By Dr. 

 C. Stanford Read. Pp. vii-f-i68. (London: 

 H. K. Lewis and Co., Ltd., 1920.) Price 

 10s. 6d. net. 



This very interesting and valuable work deals 

 with the mental disorders encountered in the Army 

 in peace and war. The author was, until the 

 time of the armistice, in charge of D block at 

 Netley, a clearing hospital through which passed 

 practically all the mental cases arising in the vari- 

 ous theatres of war. He has made every use of 

 his very exceptional opportunities, not only carry- 

 ing out careful observations and records of the 

 3000 cases which passed through his hands, but 

 also following up the later history of these cases 

 after their transfer from Netley to other hospitals. 



Detailed descriptions of the various forms of 

 mental disorder are given, together with statistical 

 facts and charts illustrating their frequency and 

 incidence ; and the military organisation developed 

 during the war to deal with the sufferers from 

 mental disease is interestingly described. The 

 author belongs to the school which believes that 

 mental disorders are essentially biogenetic, and 

 that they are the result of a failure on the part 

 of the organism to adapt itself to the environ- 

 ment in which it has to live. In this failure of 

 adaptation an essential part is played by psycho- 

 logical factors, and throughout the book emphasis 

 is laid upon their importance. A preliminary 

 chapter on the psychology of the soldier deals 

 with the various mental forces the action and 

 interaction of which may lead to the outbreak of 

 disorder. 



The book is essentially a medical work, and 

 can scarcely be recommended to those without 

 technical knowledge of the subject, but it should 

 prove of the utmost value to the psychiatrist, and 

 constitutes a noteworthy addition to the medical 

 library of the war. 



NO. 2659, VOL. 106] 



Wasp Studies Afield. By P. Rau and Nellie Rau. 



Pp. XV + 372. (Princeton : University Press ; 



London: Oxford University Press, 1918.) 



Price 85. 6d. net. 

 To those surveying the boundary between instinct 

 and reason there is no more fruitful field than the 

 fossorial wasps, with which this book is chiefly 

 concerned. The greater part of Mr. and Mrs. 

 Rau's illuminating volume is descriptive of the 

 actions of individuals; but the last chapter is an 

 impartial judicial summary, from which we ex- 

 tract the following items : — (i) There are very 

 definite and ironclad instincts. (2) Despite these 

 instincts, which are constant in each species, there 

 is much variation in the behaviour of the indi- 

 viduals. (3) There is a display of the expression 

 of emotions. (4) There is much aptitude for learn- 

 ing, display of memory, profiting by experience, 

 and what seems to us rational conduct. No reader 

 of these pages can deny that these conclusions are 

 abundantly justified by the facts narrated. 



The most complete portion of the present work 

 is the careful series of experiments on the "hom- 

 ing" of the social wasp Polistes pallipes. These 

 prove beyond question that "homing" is no 

 special faculty, but depends entirely upon experi-. 

 ence and associative memory of surrounding 

 objects. 



A few misprints, e.g. "most " for "moist," 

 P- 347i "filling" for "filling," p. 363, and the 

 omission of a whole line after 1. 8, p. 365, require 

 attention if further editions of this otherwise 

 admirable work are contemplated. O. H. L. 



Internal-Combustion Engines : Their Principles and 



Application to Automobile, Aircraft, and Marine 



Purposes. By Lieut. -Commr. Wallace L. Lind, 



U.S.N. Pp. v + 225. (Boston and London: Ginn 



and Co., 1920.) Price 105. net. 

 Commander Lind addresses his preface from the 

 United States Naval Academy at Annapolis, and 

 the book doubtless represents the instruction there 

 given on the subject of the internal-combustion 

 engine. For such a purpose the book is very well 

 suited : the theoretical work is sufficiently elemen- 

 tary, and the sections describing practice, although 

 apparently slight, are just such as young cadets can 

 grasp and appreciate, whilst realising how much 

 there is behind to be worked at if they should think 

 of preparing themselves for specialist courses. 

 Such books are sui generis — they make little appeal 

 to trained engineers and are too vague for uni- 

 versity courses, but for their own special purposes 

 they are excellent. They enable an officer to have 

 enough general knowledge to give adequate direc- 

 tions to the ratings under him. 



The sections devoted to motor fuels and 

 carburettors are much fuller than the rest of 

 the book, and are evidently written by one who 

 has given special attention to these topics. The 

 point of view is American, and the illustrations 

 mainly relate to trans-.^tlantic models, though 

 reference is made to some of the more important 

 European types — quaintly mentioned in one place 

 as those of the "belligerent nations of Europe." 



