430 



NATURE 



[February 2, 191 1 



of roses, leaf-spot {Septoria rosae) and tumour 

 ■{Botryosphaeria diplodia) are not given. This part 

 of the book might have been condensed with advan- 

 tage. Dr. Schwartz has a more extensive task in 

 describing the insect pests, of which more than a 

 hundred are known. About fifty species are shortly 

 described and tabulated according to the parts of the 

 plants which they injure. The data given are as full 

 as could be expected, and remedies are mentioned. 



OUR BOOK SHELF. 



Exercises in Metal Work. For Trade Preparatory 

 Schools. By A. T. J. Kersey. Pp. x + 70. (Lon- 

 don : G. Bell and Sons, Ltd., 1910.) Price is. 6d. 

 net. 

 Twenty-seven exercises in detail are contained in 

 this book, and hints for continuing thereafter a course 

 in metal-work suitable for pupils in trade preparatory 

 schools. The exercises are carefully graduated, at 

 first introducing the use of hand tools, and leading 

 up to some simple exercises in the use of machine 

 tools, such as drilling machines, shaping machines, 

 and turning lathes. The drawings are good, and 

 show in every case what is required of the pupil. 

 Some little omissions occur here and there; for 

 example, on p. 53 appear drawings of a V block as 

 an example of the use of a shaping machine. It is 

 customary to have a groove at the bottom of the V 

 in order to facilitate finishing its faces ; this has been 

 omitted. It is not, however, a grave objection to find 

 such details left out ; students possessed of average 

 intelligence will discover them, and, judging from the 

 preface, it is more than probable that the author had 

 this view before him in the production of the book. 



We can commend heartily the reading of the 

 author's preface to any teacher or other person having 

 an interest in workshop classes. The value of a 

 sympathetic teacher cannot be over-estimated ; it is 

 often difficult for an instructor who has been trained 

 in an engineering works (and this is essential) to 

 realise the difficulties of the bov who has just left the 

 elementary school. Unless he bears in mind the mis- 

 takes and troubles of his own early apprentice davs, 

 he is apt to be impatient. Pupils should be en- 

 couraged to think out answers to home-work ques- 

 tions. Those appearing in the book are designed 

 with the view of cultivating the spirit of inquirv and 

 of teachinT pupils to think about their work, as mere 

 manipulative skill is of little value without this — the 

 true aim of all education, technical or otherwise. 

 We can commend this book as an intelligent attempt 

 to assist in carrying- out these broad-minded prin- 

 ciples. 



A Lecture on Mendelism. By Dr. H. Drinkwater, 

 F.R.S. Pp. iii + 31. (London: J. M. Dent and 

 Sons, Ltd., 1910.) 

 In this book is given a popular lecture on Mendelian 

 heieditv, printed apparently with hardly any altera- 

 tion ; and considered as a lecture it is distinctlv good. 

 It is very simply and clearly written, and with the 

 help of the numerous diagrams and figures should 

 make the main outlines of the subject clear to those 

 who have no previous acquaintance with it. It has, 

 however, the unavoidable defect of a lecture, that to 

 avoid confusion essentials must be emphasised to the 

 exclusion of the less important; it would probably 

 have been improved by the addition of footnotes in 

 some places, amplifying or qualifying the statements 

 in the text. For example, the inference (p. 21) that 

 ''plants and animals arc built up of a number of 

 indivisible unit factors uhon which their characters 



NO. 2153, VOL. S5I 



depend " (author's italics) surely requires a qualify- 

 ing note to the effect that such unit factors mav 

 equally possibly be superposed on a basis which i- 

 dilTerent in nature. 



The figures and diagrams arc mostly clear and good, 

 and there are well-reproduced portraits of Profs. Bate- 

 son and Punnett, in addition to a frontispiece ot 

 Gregor Mendel. The representation of a wrinkled 

 seed in Fig. 5 is misleading, and the figure on thi 

 last page, illustrating the union of germ-cells, beside^ 

 being rather obscure without further explanation, 

 contains an inaccuracy in reproduction which might 

 be confusing. Other small points which could be 

 improved are the explanation of the 3 : i ratio, and 

 the use of the symbols Fj, Fij, instead of the con- 

 ventional Fi, F2. We have perhaps unduly empha- 

 sised the small defects in what should prove an 

 excellent introduction to the subject for those whu 

 read of it for the first time. L. D. 



The Application of Logic. By Alfred Sidgwick. Pp. 



ix-i-321. (London: Macmillan and Co., Ltd., 1910.) 



55. net. 

 " Throughout this book ' formal ' logic is identified 

 not only with the logic which expressly calls itself 

 formal, or * deductive,' but with any logic which, like 

 the ordinary ' inductive ' logic, is, in fact, more 

 formal than it professes to be. Wherever actual 

 application and its difficulties are ignored, there is 

 formality of a harmful kind." 



Accordingly, Mr. Sidgwick discusses such matters 

 as the ground of an inference, causal inquiries, 

 ambiguity, indefiniteness, error, begging the question, 

 distinction and definition, and thfe like, making con- 

 stant use of well-chosen illustrative cases, and writ- 

 ing always in attractive and lucid style. There is 

 some good protestation against slovenly modern usage 

 of words. Why should " transpire " be allowed to 

 mean "happen," "phenomenal" to mean "extra- 

 ordinary"? We are much to blame in this; 'tis too 

 much proved. 



On general counts, Mr. Sidgwick views his sub- 

 ject from the point of view of Dr. F. C. S. Schiller. 

 Vcrgiftungen durch Pflanzen und Pflanzenstoffe : eiii 



Grundriss der vegetalen Toxikologie fiir praktischc 



Aerzte, Apotheker und Botaniker. By Dr. F. 



Kanngiesser. Pp. iv + 49. (Jena: G. Fischer, 



1910.) Price I mark. 

 This little work deals in a verj- concise form with 

 the toxic nature and effects of various plants and 

 plant-constituents ; it is, in fact, a brief outline of 

 vegetable toxicology. 



In the first chapter the subject is dealt with from a 

 general point of view, the symptoms that usually 

 follow the ingestion of such poisonous or harmful 

 substances being considered, as well as the means 

 that may be adopted as remedies. In the following 

 chapters a short account of the .more important toxic 

 plants and plant-constituents is given, accompanied 

 in each case with the most striking symptoms it 

 produces. 



The author has certainly succeeded in compressing 

 a large amount of information into a very small com- 

 pass, and has produced a work that will be useful 

 t) phvsician and pharmacist, especially to such as 

 reside in the country, where the accidental poisoning 

 of children bv eating toxic fruits and roots is unfor- 

 tunately no rare occurrence. The book is remarkably 

 free from error, but Lobelia inilata, Tanius communis. 

 Delphinium Staphisagria, Gratiola officinalis, and 

 some others might well have been included in the list 

 of toxic plants, while Dr. Mitlacher's verv useful work 

 on toxic plants and vegetable drugs might have found 

 a place in the bibliography. 



Henry G. Greenish. 



