NATURE 



[October 30, 1890 



thoroughly and profoundly acquainted with his subject, 

 so that in a popular rhumd facts should assume their 

 due perspective — that mole-hills be not amplified into a 

 bizarre prominence, or that the great mountain tracts 

 encircling the subordinate features of the territory lose 

 not in the distant "haze their outlines— in other words, 

 that principles be clearly enunciated, and inductions 

 marshalled in harmonious sequence. The next pre- 

 requisite qualification is a keen realization of the obstacles 

 which beset his own path of observation ; those knotty 

 points, those complex junctions^of thought which cause so 

 much delay in the history of all intellectual effort. The 

 most learned authorities are often the most laboured and 

 tedious exponents of their craft ; but we have only to 

 glance at the essays and popular lectures of Clifford, 

 Tyndall, Huxley, or Haeckel, to learn what a degree of 

 excellence is thus attainable by a profound thinker and a 

 cultured mind. It is on account of the rarity of this style 

 of writing that we hail with pleasure the appearance of 

 Dr. Mercier's book, which is an excellent example of 

 the perspicuity with which a cultured mind can delineate 

 an obscure and difficult subject. Dr. Mercier's numerous 

 contributions to psychological literature which have 

 appeared from time to time in Brain, Mind, the Journal of 

 Mental Science, and his book on the " Nervous System 

 and the Mind," are a sufficient pledge of his capacity for 

 a graceful handling of the subject of insanity. After a 

 preliminary sketch of the mechanism of the nervous 

 system, and the modern view of its mental correlate, 

 given in simple but pleasing outline, the author devotes 

 his fourth chapter to a discussion on the " Nature of 

 Insanity," which he defines as a disorder in the. process of 

 adjustment of the organism to its environment — a disorder 

 not subject to correction. The faulty adaptation of 

 organism to environment is fully considered, and all 

 qualifications in any such definition of insanity are 

 lucidly expressed. 



In this chapter above all others the author exhibits 

 his analytic abilities and discriminative capacities to 

 greatest advantage, and the conception of the nature of 

 insanity so framed is to our minds a mental synthesis 

 which has remained unchallenged since first enunciated 

 by Dr. Mercier in 1882. In this connection he makes 

 the trite remark that such process of adjustment is 

 simplified by a simplification of the environment, and 

 hence the major utility of asylum treatment. Un- 

 doubtedly, the moral factor will long remain the most 

 important in the treatment of insanity ; and here Dr. 

 Mercier would seem at one with Dr. Clifford Allbutt, who 

 with becoming pungency ridiculed the idea of " curing 

 insanity out of the bottle." 



The following six chapters are devoted to etiological 

 inquiries, and the causes of insanity are grouped under 

 the headings of heredity, direct and indirect strain, 

 neurotic instability, the laws of inheritance. Reversion 

 and its limitations by the "massive pressure of race 

 heredity" are ably discussed, as is also prepotence in its 

 relations to insanity. The potency of the moral factor 

 in the production of insanity, always tinctured with more 

 or less mystery to the laity, is largely developed by the 

 author, and reduced to its simple elementary terms ; in 

 fact, the work before us is calculated very largely to 

 remove the repellent aspects of insanity which so long 

 NO. 1096, VOL. 42] 



have been created by ignorance and a false appreciation 

 of its nature. 



With respect to the community of origin of the re- 

 ligious and sexual instincts, we cannot find ourselves in 

 accord with Dr. Mercier's views ; throughout his argument 

 we believe he places undue emphasis on the significance 

 of the sacrificial element. Cogent as are the arguments 

 so frequently used to indicate such hneal relationship, 

 we think equally strong reasons may be advanced to show 

 that the development is along parallel lines of contiguity, 

 rather than the sublimation of the religious out of the 

 sexual element. The concluding five chapters deal with 

 the various forms of insanity ; and the vagaries of the 

 insane mind are graphically registered in these short but 

 concise and interesting delineations. We congratulate 

 Dr. Mercier on the production of a work which deserves 

 a widespread popularity. W. B. L. 



OUR BOOK SHELF. 



A Guide to the Literature of Sugar : a Book of Reference 

 for Chemists, Botanists, Librariatts, Manufacturers, 

 and Planters, with a Comprehensive Subject-Index. 

 By H. Ling Roth. (London : Kegan Paul, Trench, 

 Triibner, and Co., Limited, 1890.) 

 Although published in 1890, it is right to say that this 

 compilation only brings our knowledge down to the be- 

 ginning of the year 1885. It is intended to have a sup- 

 plement ready soon, and to bring the work up to date. 

 In the meantime we can speak highly of the evident care 

 and labour bestowed on this volume by the compiler. 

 The arrangement is based on that of Mr. Daydon Jack- 

 son's " Vegetable Technology." There is a catalogue of 

 authors, a list of anonymous publications, a list of periodi- 

 cals, a list of Parliamentary publications, and a chrono- 

 logical table. The first part of the latter is taken from 

 Drr Falconer's " Sketch of Sugar in Early Times " (1796). 

 The comprehensive subject-index forms a very valuable 

 part of the work. It is arranged in sections as follows : — 

 Bibliography and History, Statistics and General Economy, 

 Illustrations, Geographical Distribution, Chemistry, Origin 

 of Vegetable Sugars (the various plants yielding sugars), 

 Beet Sugar, Cane Sugar, Parasites, and Distillation. It 

 will be easily seen that this guide to the literature of 

 sugar covers practically the whole field in regard to 

 vegetable sugars. It is a work that will- prove of much 

 interest to numerous readers having to do with the cul- 

 tivation and manufacture of sugar, whether derived from 

 the sugar-cane, beet, sorghum, palm, maple, or maize. 

 We only hope the compiler will be encouraged to bring 

 out the promised supplement. During the last five years 

 considerable activity has been displayed in the United 

 States in regard to the production of sugar from sorghum; 

 and there is, besides, the very important fact that the 

 sugar-cane has recently been shown to produce mature 

 seed, and possibly capable of improvement by seminal 

 selection. The literature in regard to this point alone is 

 well worthy of being carefully traced. , D. M. 



Practical Plane and Solid Geometry. By I. H. Morris. 



(London : Longmans, Green, and Co., 1890.) 

 Students will find this work to be a most instructive 

 course, arranged in such a way that no external aid will 

 be required. Section I. begins at the very beginning of 

 the subject, and in it there are many problems dealing with 

 lines, areas, use of scales, plans and elevations of solids, 

 sections, &c. Section II. treats of descriptive geometry ; 

 and various problems on the projections of lines, oblique 

 surfaces, and solids are given, and thoroughly worked 

 out. The concluding chapter of this section is devoted 



