364 



NA TURE 



\_Feb. 18, 1886 



class of variations are 'those according to heigh/, ihzX is 

 to say, those shown by corresponding sections of dijfereut 

 segments of the stem. Fourthly, and lastly, we have 

 variations according to the biological conditions. 



The first chapter contains a detailed account of the 

 structure of " segment i " of the principal stem, i.e. the 

 segment including the node next above the cotyledons. 

 In the succeeding chapters the anatomy of the segments 

 superior to segment i, and the development of an apex 

 of large diameter are treated of. The fourth chapter 

 deals with the hypocotyledonary axis, under which term 

 the radicle of the embryo is included. 



The second part treats in a corresponding manner of 

 the leaf, only here the cotyledons first receive attention, 

 then the leaves next above them, and so on. The in- 

 creasing complication of structure along the sub-aerial 

 stems, and the converse degradation along those which 

 are subterranean, form the subject of a special chapter. 



In the third part the variations in the structure of the 

 root according to age and height are considered, the sub- 

 ject of apical development having a chapter to itself. 



The method of successive transverse sections was used 

 throughout the investigation. 



The author compares the constantly increasing com- 

 plexity of the successive segments of the principal stem 

 to an accelerated movement, the amount of the accelera- 

 tion varying according to the biological conditions. This 

 strikes us as a neat mode of expression. 



The author's account of the progress of secondary 

 thickening in the stem is interesting, especially the obser- 

 vation that in the lower segments cauline plates of 

 vascular tissue of secondary origin occupy the same 

 position as that assumed by additional primary bundles 

 in the more complicated segments above them. This 

 and similar facts lead the author to a generalisation which 

 he expresses in a phraseology adapted from Haeckel's 

 famous law, namely, that " the organogeny of the stem 

 repeats its ontogeny.'' 



We must enter a protest against the use of the word 

 " cambiform " for cambium which gives rise to secondary 

 fundamental tissue. The word cambiform has long been 

 used for certain cells of the phloem-parenchyma, and we 

 already have quite ambiguities enough in the use of the 

 word cambium and its derivatives. 



The work concludes with the expression of the author's 

 conviction that vegetable comparative anatomy demands 

 a knowledge of the structure throughout the whole extent, 

 and at all ages of the plant. A formidable task is thus 

 imposed on the anatomists of the future. D. H. S. 



OUR BOOK SHELF 



Magnetism. By Willoughby Smith. (London : November, 

 1885.) 



A PECULIAR pamphlet, said to be compiled for the instruc- 

 tion of the electrical staff of the Telegraph Construction 

 and Maintenance Company, but issued gratis by the author, 

 and devoid of any publisher. It commences with a novel 

 version of the story of the shepherd of Mount Ida, who is 

 given not only a local habitation, but a name, and it ends 

 with a material notion of lines of force which will startle 

 some of our readers. Moreover, electrical discharges, 

 magnetic clicks, &c., are "caused by the lines of force 

 adjusting themselves to each other." It contains nothing 

 new of magnetism, but it promulgates some strange 



notions. " The Great Architect of the universe employs 

 no rectilinear motions or angles." " Each atom of matter 

 possesses in itself all the properties of a magnet, and 

 emits its own lines of force." " All particles of matter, 

 solid, liquid, or gaseous, are in a polarised state, and 

 consequently emit lines of force." "The (electrical) 

 conducting properties are the result of forced polarisa- 

 tion." " Each atom composing our atmosphere is in a 

 state of polarisation, and is influenced by the magnetic 

 force emanating from the earth." " The force which is 

 called gravity is the effect of such an universal system of 

 polarisation, with which God has endowed all matter." 

 " Iron is very susceptible of polarisation from the effects 

 of what is called terrestrial magnetism (the polarised 

 atoms of the air)." 



These extracts are enough to show the tenor of the 

 paper, which will not enhance Mr. Smith's reputation. 

 He has evidently not read Airy's "Treatise on Mag- 

 netism," where it is laid down that terrestrial magnetism 

 is not produced in any important degree by magnetic 

 forces external to the earth, and it does not even 

 reside on the earth's surface. Its source must lie deep. 

 The apparatus and experiment given at p. 29 are detailed 

 more fully and clearly in Thompson's " Dynamo-Machin- 

 ery," and that at p. 41 would be more elegantly obtained 

 byHughes's induction-balance. It is curious that no refer- 

 ence should be made to the labours of Sturgeon, Scoresby, 

 W. Thomson, and Hughes, and that the laws of Lenz, 

 Jacobi, Dub, Miiller, and others are ignored. It is not a 

 pamphlet on magnetism, but a vehicle for the promulga- 

 tion of certain individual ideas, which it is to be hoped will 

 not take root among those who have been favoured with 

 the gift of this well-printed brochure. Indeed, its raison 

 d'etre is shrouded in mystery. 



An Introduction to the Osteology of the Mammalia. By 

 Wm. H. Flower, LL.D. Revised with the assistance 

 of Hans Gadow, Ph.D. Third Edition. (London : 

 Macmillan and Co., 1885.) 

 When Prof. Flower published, in 1S70, the first edition 

 of his " Introduction to the Osteology of the Mammalia," 

 the student at once recognised that he had been supplied 

 with a text-book of convenient size and form, which fur- 

 nished him with an admirable introduction to Mammalian 

 osteology. The appearance of a second edition of this 

 book in 1S76, and of a third edition at the end of last 

 year, are renewed evidence of the usefulness of the work, 

 and that it continues to be appreciated by those who are 

 engaged in the study of the anatomy of the Mammalia. 



This edition has been revised throughout, and we notice 

 in it many alterations and additions. The most import- 

 ant change is in the chapter " On tlie Classification of 

 the Mammalia," which appropriately precedes the purely 

 descriptive part of the book. This chapter has practic- 

 ally been rewritten, and embodies the introductory obser- 

 vations which the author has given to his important 

 article " Mammalia," in the ninth edition of the " Ency- 

 clopaedia Britannica." A very useful table has also been 

 introduced in connection with the chapters on the 

 vertebrre, which the author has compiled from his Cata- 

 logue of the Mammalia in the Museum of the Royal 

 College of Surgeons of England. This table gives the 

 number of the vertebra: situated in each region of the 

 spine in the skeletons of about 350 mammals, and is the 

 most complete record of the kind which has yet been 

 prepared. 



In this, as in the preceding editions, the dog's skull has 

 been taken as that from which the general description of 

 the Mammalian skull has been written, and with which 

 the study of the skull may appropriately be commenced, 

 and its description has not been changed ; but in addi- 

 tion a useful abstract of our present knowledge of the 

 development of the skull has been drawn up from Balfour's 

 " Treatise on Comparative Embryology." 



