456 



NATURE 



[Junk i6, 1910 



Here, as in several other places, Dr. O. Hertwig- 

 appears to be inconsistent, but it would be an in- 

 justice to press this charge of inconsistency too closely. 

 He is a champion of an epigenetic theory of develop- 

 ment, and argues with admirable clearness in favour 

 of the view promulgated at the same time by Driesch 

 and himself, that the destiny of any given cell in a 

 developing organism is a function of its position. At 

 the same time, he brings into account the indisputable 

 fact that the characters of the organism, and there- 

 fore of the cells composing it, are determined before- 

 hand by the constitution of the fertilised ovum from 

 which it is derived. In other words, he admits pre- 

 formation, but preformation tempered by the mutual 

 interaction of parts and the influence of external con- 

 ditions. 



There are many indications that the impartial posi- 

 tion adopted by Dr. O. Hertwig is the right one, 

 and, after all, it is the position taken up by Darwin, 

 who wrote that "there are two factors, the nature of 

 the organism, which is much the more important of 

 the two, and the nature of the conditions." But 

 latterly opinion has been sharply divided on these 

 questions, and to partisans of the preformationary or 

 epigenetic schools any attempt to reconcile such 

 apparently irreconcilable theories exposes the author 

 to the charge of inconsistency. In truth, it is very 

 difficult to draw certain conclusions from the avail- 

 able evidence, much of which appears to be con- 

 tradictory. It is the chief merit of Dr. Hertwig 's 

 work that he refuses to take extreme views, and no 

 better exposition of the middle position can be found 

 than is contained in this volume. 



COMMERCIAL ORGANIC ANALYSIS. 

 Allen's Commercial Organic Analysis. A Treatise on 

 the Properties, Modes of Assaying, and Proximate 

 Analytical Examination of the Various Organic 

 Chemicals and Products employed in the Arts, 

 Manufactures, Medicine, c2^•c. Fourth edition, vol. 

 i. Edited bv Dr. H. Leffmann and W. A. Davis. 

 Pp- x + 576. (London : J. and A. Churchill, 1909.) 

 Price 21S. net. 



'T'HE first volume of the last edition of this well- 

 J- known treatise was issued in 1898, and was 

 remarkable for the introduction of two features, 

 which have become the most striking characteristics 

 of this first volume of the new edition. These are the 

 recognition of the fact that the subjects to be dealt 

 with are so numerous and important that a single 

 compiler can no longer cope with them, and that in 

 publishing a large and important work of this kind 

 in English it is desirable to endeavour to meet the 

 needs both of readers in this country and in the United 

 States. This latter consideration is a very important 

 one, and it is to be hoped that its recognition will 

 facilitate the re-publication of other large works of 

 reference in English. 



This volume is divided into ten sections, and each 



of these is written by an expert in that branch. It will 



be a matter of satisfaction to those familiar with 



"Allen" to find that in bringing the subject-matter 



NO. 2120, VOL. 8^1 



up to date it has been possible to retain the old 

 arrangement. The introduction is written by the 

 English editor, Mr. Davis, and shows perhaps less 

 change than most of the other sections, the most 

 important additions being useful chapters on (i) 

 refractometers, (2) spectrometers and spectrographs, 

 and (3) the determination of moisture, "crude fibre," 

 and ash, all these being of sufficient general import- 

 ance to warrant their discussion in the introduction. 

 This section is, on the whole, a very satisfactory piece 

 of work, though it is rather doubtful whether it was 

 worth while to devote about three pages (53-6) to an 

 illustrated description of an arrangement for main- 

 taining a temperature constant to within a few thou- 

 sandths of a degree, since the commercial analyst is 

 not likely to want refinements of this description in 

 practice. Further, the space devoted to the "Employ- 

 ment of Immiscible Solvents " (pp. 79-82) might have 

 been much curtailed, as the present-day analyst is 

 probably perfectly familiar with the separating funnel 

 and its use. The table at the end of this section is 

 reprinted from the third edition, and should have been 

 omitted, as it is too general to be of any value, and 

 moreover, contains the inaccurate statement than 

 cantharidin, picrotoxin, and santonin are glucosides 

 It is also a mistake to refer to "saponin" as if thif 

 were a single definite substance. 



Dr. Leffmann, the American editor, contributes tw< 

 sections, the one entitled "Neutral Alcoholic Deriva 

 tives," and the other, not very happily named, " Aci< 

 Derivatives of the Alcohols." 



Notable additions are the very useful article cm 

 "Yeast" by Mr. Emil Schlichting, and the excellen 

 section on "Papers and Paper-making Material 

 by Mr. Sindall. Mr. G. C. Jones contributes th 

 sections on "Alcohols" and "Wines and PotabI 

 Spirits." Both these seem to contain all the data a 

 analvst is likely to need, but in the second sectio 

 something might have been said regarding the anaij 

 tical work on rum carried out in recent years 1 

 Jamaica and British Guiana. 



The remaining sections are those on "Sugars" an 

 " Starch and its Isomerides," both written by D 

 E. F. Armstrong. In the main, these are excellei 

 resumes of the present position of the chemistry 1 

 these subjects, and the omissions are of a trifli 

 character. In the first some reference should hi 

 been made to the detection and estimation of si 

 glucosides as salicin and strophanthin, used in me 

 cine, but possibly it is intended to deal with these un<l 

 " Drugs " in a later volume. Under " Starch" no m« 

 tion is made of the analytical characters of the " sa 

 substitutes " that are now prevalent in commert] 

 The article on gums in this section is little more th 

 a replica of that in the third edition, and it is unfc 

 tunate that the author did not take the opportun 

 of correcting the errors in it. 



The book as a whole is ver}' well edited, but the 

 are a few curious mistakes; thus in three places t' 

 name of one of the authors is written " Schlichtinj 

 and in the fourth and most important place, v- 

 at the head of his contribution, it is given ,» 

 •• Schlighting." The heading of one section is prin 3 



