NATURE 



461 



THURSDAY, SEPTEMBER 11, 1890. 



PRINCIPLES OF ORGANIC CHEMISTRY. 

 Principles of General Organic Chemistry. By Prof. E. 

 Hjelt, Helsingfors. Translated from the Author's 

 German Edition of the original work by J. Bishop 

 Tingle, Ph.D. (London : Longmans, Green, and Co., 

 1890.) 

 '■"T'HIS work is an English translation of the German 

 L edition of a book which originally appeared in 

 Swedish, and its object is stated to be " to give in a short 

 and clear form the most important points of general and 

 theoretical organic chemistry." Paraphrasing a statement 

 recently put forward by a well-known reviewer in these 

 columns, we certainly doubt the propriety of translating 

 German books of this kind into English, regarding the 

 ignorance of German by a chemist as inexcusable, if not 

 criminal : in our opinion, indeed, permission to study the 

 science of chemistry should be contingent on proof being 

 given of a competent knowledge of this language. But 

 our objection does not rest alone on this basis : we 

 should not even have recommended the translation of 

 the work from Swedish, as we hold that its study must 

 have a thoroughly demoralizing effect. It is impossible 

 " to give the most important points of general and theo- 

 retical organic chemistry," in accordance with the plan 

 adopted by the author, within so narrow a compass ; 

 and such a book can only serve the purposes of the 

 crammer. The uselessness of attempting to construct a 

 cottage from plans prepared for a mansion needs no 

 proof, but it is just such an attempt that is made in the 

 book under notice. 



The book is divided into three parts. According to 

 the translator, in Part L the composition, constitution, 

 and classification of organic compounds are discussed 

 and explained as clearly and concisely as possible. 

 Part IL is devoted to illustrating the connection between 

 the constitution of organic compounds and their chief 

 physical properties. Part II L deals with the chemical 

 behaviour of organic compounds. In illustration of the 

 treatment accorded to the various sections, it may 

 be mentioned, however, that the whole subject of " Geo- 

 metrical Isomerism," one of the most difficult of modern 

 chemical problems, is dismissed in five pages ; that 

 optical properties occupy but five and a half; and that 

 only three and a half are devoted to the discussion of 

 specific gravity and specific volume in their relation to 

 constitution. 



Some among us contend that the study of chemical 

 science affords logical training of a very high order, but 

 certainly this would not be the opinion of any intelligent 

 person unacquainted with the subject who chanced to 

 read this book. Thus, what can be the value of such 

 wretched mental pabulum as that supplied on pp. 42-43, 

 where, after the briefest possible reference to the van 

 t' Hoff-Le Bel hypothesis, we read, " Two doubly linked 

 carbon atoms would be represented by a figure consisting 

 of two tetrahedra with one edge in common. Two arrange- 

 ments are possible of substances of the type Cab = Cab. 

 Fumaric and maleic acids are examples of such com- 

 pounds " ? Then follow the two conventional double 

 NO. 1089, VOL. 42] 



tetrahedron figures, and a few lines further comes the 

 dogmatic assertion, " It can be proved that fumaric acid 

 is constituted like Pig. 2, and maleic acid like Fig. i. It 

 is not possible here to give a systematic account of the 

 principles upon which the discovery of geometrical iso- 

 merism is based." Fancy the effect of studying, let us 

 say, Euclid on such principles, and the kindly reception 

 the lad would meet with who told his master in class that 

 " it can be proved that any two sides of a triangle are 

 greater than the third," and whose knowledge went no 

 further ; yet this is about the position which a reader of 

 this book would be placed in after perusing its frag- 

 mentary sentences. If the student be exceptionally 

 intelligent, and be not satisfied with dogmatic assertions, 

 what must, moreover, be his opinion of his teacher when 

 later on he directs his attention to current literature, and 

 finds that the constitution of fumaric and maleic acids is 

 one of the questions which is being hotly contested among 

 chemists ; that it is not proved that either acid has the 

 constitution represented by the figures given ; that, in 

 fact, it is pure assumption that such is the case ; and that 

 the determination of the constitution of these and similar 

 acids is a problem of peculiar difficulty ? 



The translator tells us that " No pains have been spared 

 in order to bring the work into harmony with the latest 

 researches, though of course, from the very nature of the 

 case, all controversial matter has been excluded." The 

 first part of the sentence is distinctly misleading, and it 

 is difficult to understand the meaning of the latter. Our 

 methods of determining constitution are admittedly in so 

 many cases imperfect and but roughly approximate ; so 

 much depends on individual judgment, and the point of 

 view from which the interpretation is given ; that, in dis- 

 cussing constitution and the relation of physical properties 

 to structure, "controversy" cannot be excluded. The 

 advancing student has the right to demand a statement 

 of the arguments for and against, and to nourish him on 

 dogma is to do him a grievous injury : his object being 

 to learn to play the game himself later on, he desires to 

 obtain an insight into its rules and moves, and his only 

 chance of learning methods is to become acquainted with 

 the methods and arguments of previous workers. An 

 illustration is afforded by chapter xi., on heat of com- 

 bustion and heat of formation, which extends to the 

 inordinate length of two pages and a half. In this 

 chapter reference is made to Thomsen's calculation s of 

 the thermal values of the different kinds of bonds between 

 carbon atoms, and his conclusions are put forward in such 

 a manner as to lead the student to suppose that they are 

 based on cogent arguments. The author's preface being 

 dated Helsingfors, February 1887, it is excusable that he 

 should have been impressed by the weight of Thomsen's 

 authority ; but it is inexcusable that the translator, three 

 years later, should overlook the criticisms that have been 

 passed on Thomsen's work, and should fail to point out 

 that the conclusions which this chemist based on his 

 thermal studies of carbon compounds are frequently in 

 absolute conflict with those deduced from the study of 

 chemical behaviour. The survival at this date of the 

 strange conclusion that in acetylenic compounds the 

 carbon atoms are held together by less than no affinity 

 clearly shows that common-sense after all is an uncom- 

 mon sense. The concluding paragraph of chapter xi. is 



X 



