5o8 



NATURE 



{March 28, 



The subject of Chapter IV. (pp. 344-420) is the forma, 

 tion of organic substances from absorbed inorganic food. 

 Assimilation (in the narrower sense) is fairly described, 

 but the view taken of the action of light on the process 

 has been, perhaps, too much influenced by Pringsheim's 

 " screen-theory " of chlorophyll. Pages 380-393 contain 

 an excellent series of iigures to illustrate what is termed 

 " leaf-mosaic," or the relation of the form to the arrange- 

 ment of leaves, as insuring the exposure of the maximum 

 surface to light. At the end of the chapter the adapta- 

 tions by means of which assimilating leaves are protected 

 against the attacks of animals are well described. 



Chapter V. (pp. 421-475) treats of the metabolism and 

 translocation of food-substances (" Wandlung und Wan- 

 derung der Stoffe"). The chapter begins with a few 

 remarks on some of the characteristics of carbon com- 

 pounds. The usefulness of such a very concise treatment 

 of so vast a subject may be doubted, but the account 

 appears to be good, so far as it goes. 



The question of the first product of assimilation in 

 green plants is clearly treated, and then the chief organic 

 substances occurring in plants are described. Under the 

 head of the translocation of food-substances, the structure 

 of the phloem and of laticiferous tissue is explained, and 

 the anatomical anomalies of climbing plants are shortly 

 described from this point of view. The figures given to 

 illustrate the last-mentioned peculiarities of structure are, 

 as so often happens in such cases, diagrammatic and un- 

 satisfactory. The important subjects of respiration and 

 fermentation are also included in this chapter, and the 

 relation between these two processes is clearly brought 

 out. 



In the sixth chapter (pp. 476-544) the growth and 

 construction of the plant are treated of. Under the 

 former head we have an exposition of the mechanics of 

 growth, and of the influence upon it of light and heat. 

 The second part of the chapter includes an account of 

 cell-formation. This section, unlike the rest of the book, 

 seems to us insufficiently illustrated. Nuclear division is 

 represented in a few figures taken from Guignard,_but the 

 subject is not treated with any completeness. 



Chapter VH. (pp. 545-734), the last in the volume, is 

 devoted to general organography (" Die Pflanzengestalten 

 als vollendete Bauwerke.") The transition from uni- 

 cellular plants to the most complex forms is first rapidly 

 traced. Then we have sections dealing very fully with 

 the modifications of the leaf, the stem, and the root 

 respectively. In the first of these sections there is an 

 especially good account of the cotyledons, and many 

 interesting facts about germination are described. The 

 section on leaves ends with a short account of the mor- 

 phology of the flower. It is to be regretted that the 

 author, after severely criticizing the artificial character 

 of some former explanations of the morphology of the 

 ovule, himself makes a laboured attempt to prove that 

 the ovule is always homologous with a leaf or portion of a 

 leaf (p. 603). 



As regards the organography of the stem, special 

 attention may be called to the excellent account of the 

 stems of " lianes " (pp. 629-669), and to the clear explana- 

 tion (founded on Schwendener) of the mechanical con- 

 struction of upright stems. Here, however, as is usual 

 in such explanations, the thickened stems of Dicotyledons 



scarcely receive their due share of attention. Under the 

 heading "Hochblattstamm," the special forms of branching 

 characteristic of inflorescences are explained. 



The last section is on the construction of the root, and 

 on its movements in response to external stimuli. Full 

 justice is done to this very interesting subject, and the 

 author is quite justified in emphasizing the unsatisfactory 

 nature of those crudely mechanical explanations of these 

 phenomena which are so often given in physiological 

 treatises. 



In the rapid survey we have taken it has been difficult 

 to give a correct impression of the volume as a whole. It 

 has been necessary to notice several defects, which have 

 inevitably become more prominent in our review than 

 they are in the book itself. The work is written through- 

 out! in ^ good clear style, and if the concluding portion 

 fulfils the promise of the first volume, the treatise may 

 certainly claim to rank as the best account of the 

 vegetable kingdom, for general readers, which has yet 

 been produced. D. H. S. 



PRACTICAL ELECTRICAL MEASUREMENTS. 



Practical Electrical Measurements. By James Swinburne. 



(London: H. Alabaster, Gatehouse, and Co., 1888.) 



THIS is a suggestive little book ; and the pity is 

 that the idea of the author, in writing the 

 articles of which it is practically a reprint, has not been 

 a great deal better carried out. The articles were evi- 

 dently poor in style and excessively incomplete, even 

 taken as newspaper articles ; and, when put together in 

 a consecutive form, the " nakedness of the land " becomes 

 too painfully apparent. As it stands, the book consists 

 mainly of remarks on almost every form of instrument 

 known in electric lighting. It has no pretence to be a 

 complete treatise, even of an elementary kind, on prac- 

 tical electrical measurements in general. Many of the 

 most important branches of electric measurement are 

 not even mentioned. What we do find is, partial descrip- 

 tions of a multitude of instruments and machines, and a 

 good deal of criticism, not always in good taste, and often 

 pretty wide of the mark, of these instruments, and of the 

 ideas of other " engineers." 



The author commenced by setting himself the nearly 

 impossible task of writing articles on electric measure- 

 ment without the use of mathematical symbols. " The 

 pedantic fashion," he says, "of dragging mathematical 

 symbols into all electrical literature, and the respect com- 

 manded by an analytical investigation, even on false datar 

 often lead writers to mar work otherwise good, by getting 

 out of their mathematical depths, and writing nonsense 

 to look learned." This, which is not unlike a good deal 

 of the criticism throughout the book, sounds rather like 

 putting on grandfather's spectacles to look sage ; but, sup- 

 posing that others do drag in more mathematical symbols 

 than are absolutely necessary, it seems rather extreme to 

 punish oneself by thrusting them aside altogether. To 

 give really useful information as to the employment of 

 electrical measuring instruments without quoting the 

 formulas which are necessary in connection with them 

 and with their errors and corrections seems to us to be 

 leaving out the very crown of the whole ; and as to the 

 " respect commanded by an analytical investigation '' 



