NA TURE 



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THURSDAY, APRIL 26, 



THE NEW ORGANIC CHEMISTRY. 

 Chewie der alicyklischen Verbindungen. By Prof. 

 Ossian Aschan. Pp. xlv+1163. (Brunswick: 

 Vieweg und Sohn, 1905.) Price 40 marks. 



FEW reflections are more curious than those which 

 contrast the manifold complexity of the organic 

 chemistry of the present day with the crude simplicity 

 of the fundamental conceptions upon which it has been 

 built up. Broadly speaking, these conceptions are 

 but two in number — first, the almost repulsively 

 mechanical atomic theory of Dalton, which we still 

 retain in practically its original form, and second, 

 the irritatingly mysterious doctrine of valency intro- 

 duced by Frankland and Kekul£, also still preserved 

 much as it was enunciated, but which eludes our 

 grasp and sets us chasing shadows so soon as we 

 attempt to translate it into definite mechanical con- 

 ceptions. Yet, on the ground-work afforded by these 

 two conceptions, so irreconcilable in their nature and so 

 hopelessly crude in the eyes of the physicist, the organic 

 chemist has built up a purely experimental science 

 which embraces hundreds of thousands of different 

 substances within a scheme as perfect as any known 

 to science, which classifies with similar perfection 

 the reactions by means of which those substances are 

 produced and the behaviour which they exhibit, and 

 has led to the synthetic preparation of hosts of 

 compounds the production of which our immediate 

 predecessors regarded as amongst the most intimate 

 secrets of animal and vegetable life. 



This result has been attained by the systematic 

 development of experimental methods, and by applying 

 those methods, as they became sufficiently powerful, 

 to the consecutive study of the diverse classes of 

 compounds occurring in organic chemistry. Long 

 ago, experimental methods were sufficiently strong to 

 permit of their successful application to large numbeis 

 of aromatic compounds. To-day, the rough methods 

 of the older chemists have become largely superseded 

 by far more delicate ones, by methods which render 

 possible the building up, piece by piece, of the fragile 

 molecular structures numbered amongst the alicyclic 

 compounds. The organic chemist has probably always 

 realised the filamentary character of his hypotheses, 

 and, knowing that he has no prophetic or far-reaching 

 mathematical theory with which. to eke out his own 

 cunning, has been led to rely very largely upon his own 

 manipulative skill. For this reason, and more especially 

 is this the case in the branch of the subject now under 

 consideration, organic chemistry partakes of the 

 nature of an art as much as of that of a science, and 

 to be successful, the organic chemist must be endowed 

 with a sort of intuition which education cannot impart 

 and instruction cannot destroy. 



The systematic study of the alicyclic compounds 

 dates back only some twenty-five years. At that time 

 the wonderful successes achieved amongst the aro- 

 matic compounds by Kekule and his followers seem 

 almost to have suggested that all complex organic 

 NO. I9O4, VOL 73] 



substances might be benzene derivatives. One of the 

 most important alicyclic compounds known to us, 

 namely, camphor, was formulated by Kekule as an 

 aromatic substance, and for long the Kekule consti- 

 tution for camphor held its own, in spite of objections 

 raised by Armstrong and others. Gradually, however, 

 as the early work of Freund, and especially of W. H. 

 Perkin, jun., was developed, it became clear that 

 benzene derivatives are not the only possible closed 

 chain carbon complexes, and derivatives of 3, 4, 5, and 

 6 membered closed carbon chains were prepared 

 synthetically; it was thus demonstrated that there 

 exist in nature many important closed ring compounds 

 which belong to a class totally different from that of 

 the aromatic compounds, and which may be termed, 

 as Bamberger first suggested, the alicyclic com- 

 pounds. 



A work like the present, which aims at giving a 

 full and complete account of all that has been done in 

 a subject which has grown so rapidly, and is 

 even yet but in its childhood, is greatly needed, and 

 probably no one is better equipped for successfully 

 carrying out the colossal task involved in its produc- 

 tion than Prof. Aschan, of Helsingfors. For the 

 worker in this subject, such a book as Aschan has 

 produced is invaluable, if only as an aid to the 

 mnemonic arrangement of his knowledge, and for 

 the student, face to face with the task of studying 

 hundreds of lengthy memoirs, such a classified digest 

 of the whole subject as is here provided offers invalu- 

 able indications as to what must be read and what 

 may be safely disregarded. 



The classification adopted in the work consists 

 primarily of a division into a general and a special 

 part ; further, each division of the subject is ushered 

 in by an historical introduction, which is both 

 interesting and of considerable educational value as 

 leading up, tersely and plainly, to the main theme. 

 The general part includes an introductory chapter 

 defining the scope of the subject dealt with, a 

 theoretical discussion relating to the development of 

 the subject, a discussion as to the influence of ring 

 formation upon the chemical and physical properties 

 of ring compounds, and an exposition of the stereo- 

 chemistry of alicyclic substances. The special part 

 comprises a systematic description of the methods of 

 formation and preparation of alicyclic compounds, 

 followed by a detailed and equally systematic presen- 

 tation of our present knowledge of monocyclic, 

 bicyclic, tricyclic, and polycyclic carbon compounds. 



The variety of types and the complexity of detail 

 involved in the study of the alicyclic compounds 

 possibly make essential the primary division of the 

 work into a general and a special part ; the instances 

 which can be quoted in which some repetition results 

 from the introduction of a general summary as a 

 preliminary to the detailed section are therefore, per- 

 haps, unavoidable in a work of this kind. At the 

 same time, any duplication of matter in the general 

 summary and the detailed description has some draw- 

 backs, because it increases the actual number of pages 

 to be got through without essentially affecting the 



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