NATURE 



THURSDAY, AUGUST 7, 1913. 



MANIHOT RUBBER. 

 Der Manihot-Kautschuk. Seine Kultur, Gewin- 

 nung und Preparation. By Prof. A. Zimmer- 

 mann. Pp. ix + 34.2. (Jena: Gustav Fischer, 

 1913.) Price 9 marks. 



THE subject of rubber cultivation is one which 

 has received much attention during recent 

 years. Hitherto the Middle East has confined its 

 attention almost entirely to the cultivation of 

 Hevea brasiliensis , rather than that of Manihot, 

 which is the subject of Dr. Zimmermann's book. 

 Manihot is not regarded in the Middle East as 

 being so profitable to cultivate as Hevea brasili- 

 ensis, but it certainly takes a very high place 

 among the arborescent forms of rubber-yielding 

 plants in virtue of its rapid rate of growth, its 

 hardy characteristics, and quality of rubber. 



Four species are dealt with by the author, viz., 

 Manihot Glaziovii, Mull. Arg. ; M. dichotoma, 

 Ule; M. piauliyensis. Ule ; M. heptaphylla. The 

 first species is that which has been most largely 

 distributed throughout the tropics, and is the 

 source of " Ceara " rubber of commerce. The 

 other species have onlv recently come into promin- 

 ence, mainly as the result ol the work of Dr. Lie 

 in tropical America. 



A full description is given in chapter ii. of these 

 species and their natural habitats. The cultiva- 

 tion in different countries, the variability of the 

 plant, its anatomy, morphology, and diseases of 

 various parts are also dealt with. An interesting 

 diagram is shown, giving a good idea of the distri- 

 bution of the bands of laticiferous tissue. A trans- 

 verse section through the cortex and bark of 

 Manihot Glaziovii shows the connected tangential 

 bands of laticifers near the cambium being broken 

 up as one passes outwards; in fact, from this 

 transverse section one would be inclined to infer 

 that if the tapping instrument was pressed deep 

 enough it would, on every occasion (except where 

 it touched a medullar}' ray), puncture a laticiferous 

 vessel, and thus give rise to an exudation of latex. 



An instructive chapter deals with the various 

 methods of tapping, and a series of diagrams 

 showing the half spiral, half herring-bone, full 

 herring-bone, full spiral, and "V" tapping is 

 given. Some of the tapping implements depicted 

 are somewhat out of date, but will prove of interest 

 to the general reader. Various systems of tap- 

 ping, including pricking and vertical incisions, are 

 very well illustrated. 



The last six chapters of the book (xvi. to xxi.) 

 NO. 2284, VOL. gi] 



deal with the general research which has been done 

 in connection with rubber, and go somewhat 

 deeply into the problem of tackiness, colour, and 

 preparation of rubber. Even an account is given 

 of the proceeds and revenue from plantations, and 

 of the further uses of rubber trees. The book 

 therefore covers a very wide field, and should 

 prove of great interest to all connected with the 

 rubber industry. Dr. Zimmermann's book will 

 probably stand out for some time as one of the 

 best on species of Manihot. 



II. W. 



COMPARATIVE AX ATOMY. 

 Vorlesungen iiber vergleichende Anatomic. By 

 Prof. Otto Butschli. 2. Lieferung : Allgemeine 

 Korper- und Bewegungsmuskulatur ; Elek- 

 trische Organe und Nervensystem. Pp. iv + 

 401 — 644. (Leipzig : W. Engelmann, 1912.) 

 Price 9 marks. 



THE first volume of these lectures was re- 

 viewed in Nature in July, 191 1, and atten- 

 tion was directed to the comprehensive scope of 

 the work, the lucidity of exposition, and the 

 excellence of the simple semi-diagrammatic 

 illustrations. These qualities are fully maintained 

 in the second volume, which deals with the 

 muscular and nervous systems. 



In a work covering such an extensive field of 

 investigation it is quite impossible for one man 

 to acquire a first-hand knowledge of all the 

 material of which he treats, or even to do more 

 than sample the voluminous flood of literature 

 dealing with all the subjects discussed in such 

 lectures as these. In such circumstances it would 

 be easy for the specialist in any one branch of 

 research to criticise the facts and inferences, and 

 in many cases also the choice of interpretations 

 borrowed from other writers. But such defects, 

 which are, of course, inevitable, are more than 

 compensated by the broad, well-balanced, and; 

 consistent view the general reader obtains when 

 one competent writer surveys the whole subject. 



In recent years intensive specialisation has made 

 most of our text-books a badly-fitted patchwork 

 of the scraps of knowledge which a host of authors 

 has garnered, each in his own patch of cultiva- 

 tion ; and most students and teachers have be- 

 come only too familiar with the ill-jointed and 

 distorted ideas such books convey. In studying 

 such lectures as Butschli 's, even if one admits that 

 the detailed information may not be as accurate 

 as can be obtained in the patchwork type of book 

 by several authors, the reader gets a truer per- 

 spective, and sees the facts blended into a picture 



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