June 2, 1904] 



NA TURE 



99 



of experimental psychology to educational problems. 

 Seeing that it is the first serious treatise on the subject 

 which has yet appeared, such a pioneer work naturally 

 deserves warm welcome and temperate criticism, even 

 though there be important points of detail, both in the 

 methods employed and in the conclusions drawn, which 

 can hardly be acceptrd without reservation. As Prof. 

 Thorndike abl\- points out in the last five pages of his 

 book, there are numerous problems and experiments 

 described by him which any trained teacher " can 

 attack with a fair promise of success." His obvious 

 aim in publishing this work at the present primitive 

 stage of genetic psychology is to encourage a greater 

 number of workers in the field of research with which 

 he has so closely identified himself in the United States. 

 For tliis reason, doubtless, he has omitted all consider- 

 ation of the comparative data already available in other 

 countries than his own. 



The first two chapters are devoted to the methods of 

 measurement and to the statistical distribution of 

 mental traits within the community. The view is up- 

 held that " the distribution of any mental trait in a 

 homogeneous species undisturbed by selection is that 

 given by the probability integral." It is to be regretted 

 that the author has not devoted more space to statistical 

 methods. Such sentences as the following, on p. 20, 

 are surely unwise : — " The mathematical formulae by 

 which this is done need not concern us here." " Here 

 again the mathematical formulae are best omitted. 

 The reader may take it on trust that such a trans- 

 position as the following is correct." 



The third chapter concerns the correlation between 

 different mental abilities in the same individual. An 

 endeavour is made to define the certaintv with which 

 any scholar who is especially proficient in one subject 

 of study will surpass or fail to reach tlie average in 

 other subjects. It is experimentally shown that the 

 phrase " abllit}- in arithmetic " is " but an abstract 

 name for a number of partially independent abilities." 



The remaining chapters are concerned with experi- 

 mental work upon the connection of mental traits with 

 sex and age, upon the relation between mental and 

 physical traits, and upon the influence of heredity and 

 environment. ^^'ithi^ the limits of this notice it is 

 impossible even to summarise the many highly in- 

 teresting results of the experiments of the author and 

 his countrymen. As the author observes, 



" The science of education when it developes will 

 like other sciences rest upon direct observations of and 

 experiments on the influence of educational institu- 

 tions and methods made and reported with quantitative 

 precision. ... It is the vice or the misfortune of 

 thinkers about education to have chosen the methods 

 of philosophy or of popular thought instead of those of 

 -I irnce. We ruminate over the ideas of Pestalozzi or 

 ll'tbart or Froebel as if writing a 000k a hundred 

 M .irs ago proved a man inspired. . . . We are like 

 rhcmists who should quarrel over the views of 

 r.iracelsus or Arnauld of Villeneuve. ... In educa- 

 li'ii everything is said but nothing proved " (p. 164). 



riiis book is a worthy and welcome attempt to apply 

 exact method to educational problems, although it 

 leaves some little to be desired in style and general 

 appearance. Ch arles S. Myers. 



NO. 1S05, VOL. 70I 



OVR BOOK SHELF. 



Precis d'£lectricM MMicale, Technique Electro- 

 physiologic, £lectrodiagnostic Electrotherapie, 

 Radiologic, Photothdrapie. By Prof. E. Castex. 

 Pp. vii + 672 ; 208 figures. (Paris : F. R. de Rudeval, 



The object of the author has been to furnish the 

 medical student with a work which will be useful to 

 him in the present state of electrical knowledge, but 

 the author hopes that it will also not be without value 

 to medical men who are devoting themselves to the 

 special study of electrotherapeutics, and likewise to 

 practitioners who have not had such opportunities. 



The work is divided into five different sections, in- 

 cluding technique, electrophysiology, electrodiagnosis, 

 electrotherapy, and lastly the study of X- and other 

 rays. 



The author has been very successful in the arrange- 

 ment of his matter, and the physical aspect of the 

 question has not been neglected, judging, of course, 

 from the medical point of view. The various currents 

 employed in medicine, continuous, interrupted, sinu- 

 soidal, high-frequency, and static, have all been 

 practically and efficiently explained. The second and 

 third chapters, dealing with electrophysiology and 

 diagnosis, will be found particularly useful to those 

 who desire a practical and not too exhaustive guide. 

 The application of electricity to the diseases of the 

 different organs is described in concise and practical 

 terms, a fact which will be useful to physicians who 

 have not had the advantages of modern training at 

 one of the electric departments which now form a part 

 of most large hospitals. The last chapter, which is 

 devoted to X-rays, occupies something like 120 pages, 

 and cannot, of course, be expected to compete with the 

 larger treatises, such as Bouchard's, recently pub- 

 lished. But again Prof. Castex has shown his prac- 

 tical tendency by giving under each heading a short 

 and very useful guide to the interpretation of photo- 

 graphic as well as radioscopic diagnosis, and radio- 

 therapy itself, although briefly treated, has not been 

 forgotten. 



The work contains about 208 illustrations, well 

 chosen to assist the student in understanding the 

 theories, instruments, and clinical charts. 



A careful perusal of the work will show that it has 

 been written by one who understands his subject and 

 the needs of the student and practitioner. It is concise, 

 thoroughly practical, and just such a guide as should 

 appeal to those for whom the author has written the 

 work. J. M. 



Radium and All About It. By S. Bottone. Pp. 96; 



with four figures and four full-page plates. 



(London : Whittaker and Co., 1904.) Price is. net. 

 The appearance of a popular shilling volume dealing 

 with the properties of the salts of radium and the 

 theory of radio-activity may be regarded as an indica- 

 tion of the wide interest that has been aroused by the 

 discovery and investigation of the radio-active elements. 

 There is much to be said in favour of the production 

 of a book that shall satisfy the curiosity of those 

 whose interest has been aroused but whose know- 

 ledge of chemistry and physics is insufficient to enable 

 them to follow the developments of the subject in the 

 technical journals. In spite of its rainbow-tinted cover 

 and its somewhat boastful title, the present volume 

 gives a substantially accurate account of the most 

 important phenomena. It contains liberal quotations 

 'rom the chief worker^ in the subject, though these 

 are taken chiefly from articles that have appeared in 

 the non-technical journals and reviews. The author 

 appears to have derived his information almost entirely 



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