;o2 



NATURE 



[January 5, 191 r 



under-cooling and the metastable state ; diffusion in 

 the solid state ; physical properties of alloys ; and 

 electromotive force and corrosion. In chapter xiv. the 

 construction of the equilibrium diagram is clearly 

 explained, and the remainder of the book deals 

 with the condition of metals in alloys, plastic deforma- 

 tion, the metallography of iron and steel, and the 

 metallography of industrial alloys. 



The present writer has made many notes on points 

 in these chapters, as p. 222, "white cast-iron, marten- 

 site and cementite," instead of pearlite and cementite. 

 The author is good on the difficult subject 

 of hardness. P. 276, aluminium alloys have " a 

 lower hysteresis than the purest specimens of iron 

 . . . probably due to ... removing oxygen." This 

 is more likely to be due to the larger crystals formed, 

 and the author, in such a theoretical work, might use 

 the term "crystal" occasionally instead of "crystal 

 grain." 



In the chapter on the metallography of iron and 

 steel there is so much that is erroneous that it is im- 

 possible to deal with it properly, but as an example 

 the statement on p. 374 that "A tool steel containing 

 i"6 per cent, carbon, quenched from 800° C. in ice- 

 water, consists of pure martensite," is meaningless. 



The work is, however, one that every student of 

 metallography should possess, for although there are 

 so many points in it with which one does not agree, 

 the author has given on the whole a fair account of 

 theoretical matters connected with metallography, has 

 scoured the literature of the subject, even extending 

 to Russian, and has giv^en copious references which 

 must prove useful to those investigating the problems 

 of metallography, who desire with a minimum expen- 

 diture of time to find out what has been done on their 

 particular branch. A. McWilliam. 



PHYSIOLOGICAL CHEMISTRY. 

 Practical Physiological Chemistry. By Dr. R. H. 

 Aders Plimmer. Pp. viii + 270. (London: Long- 

 mans, Green and Co., 19 10.) Price 65. net. 

 THIS is really the second edition of Dr. Aders 

 Plimmer's excellent manual. The first appear- 

 ance of the book was privately printed for use in the 

 practical classes of physiological chemistry at Univer- 

 sity College, London, but a good many copies were 

 distributed to other teachers, and to the Press. A 

 favourable notice of this preliminary edition appeared 

 in the pages of Nature at the time. The publication 

 of the book for general sale is an indication of the 

 way in which the teachers of the subject welcomed 

 the new departure in the presentation of the subject. 

 For it is a new departure ; hitherto works on the 

 subject have been written by physiologists ; the pre- 

 sent book is written by a chemist ; it is physiological 

 chemistry as opposed to chemical physiology. 



The increasing exactitude of knowledge in the 

 chemistry of those carbon compounds which are the 

 constituents or products of living matter warrants the 

 appearance of a book written to show that physio- 

 logical chemistry is only a branch of organic chemistry, 

 and Dr. Aders Plimmers has been successful in show- 

 ing the connection of the two by the insertion of the 

 appropriate and logical links which unite the intro- 

 NO. 2149, VOL. 85] 



ductory chapters on organic chemistry proper with 

 its daughter science. 



The main aim of the work is to make it a trust- 

 worthy practical guide, and no laboratory worker 

 can afford to be without it. Its ideal is that every 

 student shall work through all the exercises; these 

 are set out with detail and in a clear manner, so that 

 there is no reason why the student should fail to do 

 so under his teachers, except that of time, and time 

 is a very important factor for students of medicine, 

 to whom the work is primarily addressed. In the 

 medical curriculum, the number of subjects is grow- 

 ing every year, and each one of these is expanding 

 and seeking to encroach more and more on the un- 

 fortunate student's already too-full day. Teachers 

 are already seeking means to Ihnit in particular 

 certain preliminary subjects, and to exclude those 

 portions which have but little direct bearing on his 

 future practical life. There is no subject, however, 

 which has such a direct bearing on medical practice 

 as phjsiological chemistry ; its relationships to 

 pathology become clearer with everj' advance in know- 

 ledge ; if there is one subject more than any other 

 which should not be curtailed, that subject is 

 physiological chemistry. W. D. H. 



SYSTEMATIC BOTANY. 

 Das Pflanzenreich. Regni vegetabilis conspectus. 

 Edited by A. Engler, Vol. iv., pt. 104. Papa- 

 veraccae-Hypecoideae et Papaveraceae-Papaveroi- 

 deae. By Friedrich Fedde. Pp. 430. (Leipzig : W. 

 Engelmann, 1909.) Price 21.60 marks. 



THIS volume forms the fortieth part of the great 

 series of nionographs in course of publication 

 under Dr. Engler 's editorship. It comprises the family 

 Papaveraceae as understood in the restricted sense, 

 that is, without the Fumariaceae ; the account 

 of these will be issued subsequently as Papaveraceae- 

 Fumarioideae. The special portion of the work, the 

 systematic treatment of genera and species, is pre- 

 ceded by a general account of the family occupying 

 eighty-three pages, in which Dr. Fedde discusses the 

 morphology and anatomy of the vegetative organs. 

 with special reference to the value for systematic 

 purposes of the anatomical characters ; the position of 

 the laticiferous vessels and the character of the latex 

 is found most helpful in this respect. The floral 

 structure and its modifications are discussed at con- 

 siderable length, and also the fruit, especially the 

 various mechanisms of dehiscence. There is also a 

 useful section on geographical distribution, a discus- 

 sion of the affinities of the family, and an account of 

 its economic uses. 



The great value of these monographs lies, however, 

 in the systematic portion, which should represent the 

 results of the work of an expert student of the family 

 on all the available material. Dr. Fedde is known as 

 an authority on the Papaveraceae, and we look to his 

 monograph for a careful and considered systematic 

 presentation of the family. It is somewhat surprising 

 therefore to note the treatment of the earlier genera 

 of Papaveroideae which, as Platystemon and Esch- 

 scholtzia, are confined to Pacific North America, in 



