March 20, 1890] 



NATURE 



461 



possible, drains for its own use the entire cerebral 

 activity. 

 Attention from the first has had a biological value. 



"Any animal so organized that the impressions of the 

 external world were all of equal significance to it, in 

 whose consciousness all impressions stood upon the same 

 level, without any single one predominating or inducing 

 an appropriate motory adaptation, were exceedingly ill- 

 equipped for its own preservation." 



Attention has thus been a factor in the progress of life, 

 or, as Prof. Ribot puts it epigrammatically, attention is a 

 condition of life. In the lower animals, under normal 

 conditions, attention is for the most part spontaneous ; 

 or, to use the author's alternative term, natural. One 

 may perhaps say that in natural or spontaneous attention 

 the motive or interest is inherent, while in voluntary or 

 artificial attention it is extraneous. And the process by 

 which voluntary attention is developed is by rendering 

 attractive by artifice what is not attractive by nature ; 

 by giving an artificial interest to things that have not a 

 natural interest. This, too, is a factor in progress ; this, 

 too, has a biological value. 



•'In the course of man's development from the savage 

 state, so soon as (through whatever actual causes, such 

 as lack of game, density of population, sterility of soil, 

 or more warlike neighbouring tribes) there was only left 

 the alternative of perishing or of accommodating oneself 

 to more complex conditions of life — in other words, going 

 to work— voluntary attention became a foremost factor 

 in this new form of the struggle for existence. So soon 

 as man had become capable of devoting himself to any 

 task that possessed no immediate attraction, but accepted 

 as only means of livelihood, voluntary attention put in 

 an appearance in the world. It originated, accordingly, 

 under the pressure of necessity, and of the education 

 imparted by things external." 



We have thought it more just to our author, and more 

 satisfactory to our readers, to give some account of Prof. 

 Ribot's main theses with which we are in full sympathy, 

 than to select minor points, of which there are but few, in 

 which we differ from his conclusions. The translation is, 

 on the whole, satisfactory, but some expressions, such as 

 ^* the marrow and the bulb " (for the spinal cord and 

 medulla), " moderatory centres," and " the fundament of 

 emotional life rests in tendencies," &c., strike one as 

 somewhat unusual. C. Ll. M. 



OUR BOOK SHELF. 



Handleiding tot de Kennis der Flora van Nederlandsch 

 Indie : Beschrijving van de Families en Geslachten der 

 Nederl. Indische Phanerogamen. Door Dr. J. G. 

 Boerlage. Eerste Deel, Eerste Stuk. " Ranunculaceae 

 — Moringaceae.'' Pp. 312. With an Index. (" Intro- 

 duction to a Knowledge of the Flora of the Dutch East 

 Indies." (Leyden: E. J. Brill, 1890.) 



This is the first part of a work consisting of descriptions 

 of the natural orders and genera of flowering plants repre- 

 sented in the Dutch East Indies. A work thus limited 

 must necessarily be of limited utility ; but we have Dr. 

 Treub's testimony in a preface thereto that he regards it 

 as a highly useful forerunner of a new Flora of the 

 country. It is nearly five-and-thirty years since Miquel 

 began publishing his " Flora," and the last part of it 

 appeared in i860, before Bentham and Hooker's " Genera 

 Plantarum " commenced ; and systematic botany gener- 



ally has experienced extraordinary development since 

 then. Further, one of the great advantages claimed for 

 the present work is that it is wholly in Dutch. It is 

 based on Bentham and Hooker's *' Genera Plantarum," 

 and we find on comparison that the ordinal, tribual, and 

 generic definitions are to a great extent translations, 

 though later additions to the flora, both in genera and 

 species, have not been neglected. Dr. Boerlage' s book 

 will also be useful to the phytographer, as it is already 

 something to have a synopsis of the genera found in 

 the large eastern area under Dutch dominion. Geo- 

 graphically, the next descriptive "Flora" of the region 

 should include the whole of " India aquosa," which 

 means, at least, an examination of the plants of the 

 whole of tropical Asia, of tropical Australia, and of Poly- 

 nesia. Such a work, on lines similar to Hoolcer's " Flora 

 of British India," would be of immense value ; but it 

 requires qualified men, with sufficient time, money, and 

 ample materials from the whole area. W. B. H. 



The Elements of Laboratory Work. By A. G. Earl, M.A., 

 F.C.S. (London : Longmans, Green, and Co., 1890.) 



This volume is of such a character that the reader is at 

 once tempted to seek for its excellences rather than for its 

 weak points. It aims at presenting " an introduction to 

 all branches of natural science," and is intended to be 

 used as a hand-book in the laboratories of public schools 

 that have well-equipped rooms devoted to practical science. 

 The author says in his preface that such rooms " are now- 

 adays considered a necessary part of all public schools and 

 colleges." Granting that this is the case, that the teacher 

 is good, and that his pupils are already highly trained 

 and anxious to learn pure science for its own sake, this 

 volume might be accepted as an excellent guide. It is 

 marked by a total absence of the " familiar examples " 

 which we have hitherto associated with elementary 

 scientific works. The student is made to accustom him- 

 self to technical language from the very first. For example, 

 " a set of weights^'' is, on p. 2, explained as being " a 

 number of bodies so arranged," &c. ; and a few paragraphs 

 further on the student is directed to " verify the graduation 

 of a burette," and is introduced to reading telescopes and 

 cathetometers. The first introduction of the student to 

 chemical changes is an experiment consisting of the igni- 

 tion of silver nitrate with quantitative observations, the 

 second experiment is similar but with silver iodate, and 

 the third is the heating of silver nitrate in a closed tube 

 over a small Bunsen flame. In an explanation of the 

 significance of what are commonly known as atomic 

 weights and -molecular weights, the expressions atomic 

 masses and molecular masses are used. We do not see 

 the advantage of this novel nomenclature. If the volume 

 had an index, we should be prepared to recommend it in 

 unqualified terms for the use of school-boys who can 

 carry out such instructions as the following : " Perform ex- 

 periments illustrating the law that chemical combination 

 takes place between definite quantities of different kinds 

 of matter." 



Magnetism and Electricity. Part II. Voltaic Electricity. 

 By Prof. Jamieson, M.Inst.C.E., &c. (London : Griffin 

 and Co., 1890.) 



If the third part of this work prove equal in excellence 

 to the two already pubhshed. Prof. Jamieson may claim 

 to have produced one of the best introductory text-books 

 on the subject. Like its predecessor. Part II. treats the 

 subject in an essentially practical way. A competent 

 electrician himself, the author is well able to understand 

 the difficulties which beginners are Hkely to meet with, 

 and his attempts to make obscure things clear will prob- 

 ably be found highly successful. The theoretical side of 

 the subject is carefully considered, and no important 

 application of a principle is passed over without reference. 



