442 



NA TURE 



[August 30, 1906 



quitoes " (not knowing that the terms gnats _ and 

 mosquitoes are applied indiscriminately to any bitmg 

 species of Culicidae), and, what is more important, 

 the gnats belonging to the genus Anopheles, though 

 far from extinct in England, have ceased to dis- 

 seminate ague as formerly. 



Mr. Austen informs us that there are practically 

 only six families of blood-sucking flies in England, 

 Chironomida; (midges), Culicidae (gnats or mosqui- 

 toes) Simulidse, Tabanidae (horse-flies), Muscids, and 

 Hippoboscids. In Chironomidae and Muscidse the i 

 habit is exceptional, occurring in a few species only, I 

 and, except in the Muscida (and perhaps the Hippo- 

 boscidje), the habit is confined to the females. Mos- 

 quitoes, however, are also capable of subsisting on 

 the juices of plants. 



The illustrations in the present work are consider- 

 ably enlarged, and with few exceptions represent only 

 females. The originals have been prepared for ex- 

 hibition in the north hall of the Natural Historv 

 Museum. Tlie letterpress consists of a brief general 

 account of each family, and a notice of the chief 

 characteristics, habits, and localities of the various 

 species figured, technical descriptions, however, being 

 omitted. Little has been done in England to 

 popularise the study of Diptera, and there are very 

 few illustrations of the species; so we welcome this 

 excellently arranged and illustrated book as a useful 

 contribution to our knowledge of the British Diptera. 



VV. F. K. 



Gehirn und Uiickenmark. Leitfaden fur das Stiidium 

 der Morphologic und des Faserverlaufs. By Dr. 

 Emil Villiger. Pp. vii+ 187 ; illustrated. (Leipzig: 

 W. Engelmann, 1905.) Price 9 marks. 

 There is no department of medical science in which 

 greater advances have been made within the last 

 twenty-five years than in that of diseases of the 

 central nervous system. This is mainly a result of 

 increasing precision in our knowledge of the compli- 

 cated labyrinth of the various groups of nerve-cells 

 and nerve-fibres which compose the essential mech- 

 anism of the nervous system. The complexity of 

 the subject renders it a task of some difficulty to the 

 medical student, whether he be undergraduate or 

 post-graduate, who is desirous of acquiring that 

 thorough grasp of nervous anatomy on which the 

 successful solution of diagnostic problems must of 

 necessity depend. To such students as are able to 

 read German we can cordially recommend Dr. 

 Villiger's book. Within the compass of 177 pages 

 the author discusses in lucid style the main facts of 

 the morphology of the brain and spinal cord, and 

 describes all the more important tracts of nerve-fibres. 

 .'\n excellent series of illustrations, many of them 

 original, illuminate the text, whilst we are glad to 

 observe that the author evidently describes the gross 

 anatomy as if demonstrating the actual brain, using 

 the diagrams as accessories. In this way the prac- 

 tical value of the book is undoubtedly enhanced. 



Commencing with an account of the embryological 

 development of the nervous system, the author pro- 

 ceeds to discuss in detail the naked-eye anatomy of 

 the brain and spinal cord, with their surrounding 

 membranes. An interesting historical account is 

 given of the successive stages in the methods of 

 neuro-histology, but we are surprised to find no 

 reference to Marchi's well-known osmic acid method 

 of staining recently-deg-enerated nerve-fibres, a method 

 which since its introduction more than ten years ago 

 has done more than any other to clear up our know- 

 ledge of nerve-tracts. Nor is any reference made to 

 the still more recent methods of Cajal and of 



VO. 1922, VOL. "4! 



Bielschowsky for the staining of neurofibrils. Doubt- 

 less these omissions will be rectified in a future 

 edition. 



An excellent description is given of the microscopic 

 characters of the various regions of the cerebral 

 cortex, the basal ganglia, the cerebellum, pons, 

 medulla, and spinal cord. The cranial nerves are dis- 

 cussed with remarkable clearness, the diagrams illus- 

 trating this part of the book being particularly good. 

 Finally, there is a concise account of the main 

 sensory, motor, and association systems of fibres in 

 the central nervous organ. The book is well indexed. 



Dr. Villiger is to be congratulated on having pro- 

 duced an excellent book. Not only does it amply 

 fulfil its avowed scope of serving as an introductory 

 guide to the student, but it will be read with pleasure 

 and profit by many neurologists. 



Natiirkonstanten in alphahetischer Anordnung. By 

 Prof. Dr. H. Erdmann and Dr. P. Kothner. 

 Pp. 192. (Berlin : Julius Springer, 1905.) Price 

 6 marks. 

 This handy little work is a book of constants intended 

 for the use of chemists and physicists. It differs from 

 others of its kind chiefly in the fact that the inform- 

 ation in it is arranged alphabetically, with a marginal 

 thumb index for rapid reference. 



The work of the compilers has on the whole been 

 very well done. Only one value of each constant is 

 given, and usually no reference is made to the source 

 or author. The work of the last ten years has, how- 

 ever, been incorporated to a much greater extent than 

 is usual in books of this kind, and even data only 

 published during the past twelve months are included. 

 The plan adopted by the compilers should conduce to 

 a considerable saving of time in looking up inform- 

 ation. We think the book should be of especial value 

 to chemists, as the data necessary in quantitative 

 analysis are dealt with in a specially complete manner. 

 There are also tables giving for each element and its 

 most important compounds the atomic or molecular 

 weight, density, melting point, boiling point, thermo- 

 chemical constants, &c., together with a five-figure 

 logarithm table for computation purposes. Details as 

 to the most important spectroscopic features of each 

 substance are given in a very handy form, the con- 

 ditions as to the particular spectrum b=ing clearly 

 specified. .-Xnother very useful table containing data 

 not often easily accessible is that of the electrochemical 

 equivalents of the metals. 



It is difficult in the time possible for a reviewer to 

 spend on a book of this kind to detect many of the 

 errors nearly inevitable in a first edition. The plan 

 adoDt"d by the writer has been to put the work for 

 a while on his reference shelf, and turn to it frequently 

 when lookinsr up constants, verifying from other 

 sources the data thus obtained. 



Obvious slips are the value of :Jt, given on p. 114 

 ten times too small, the E.M.F. of the Clark cell, given 

 on p. 40 as o (10735 volt, and several misprints among 

 th" tables of Eng-lish weights and measures, where 

 the p-allon is included under measures of surface. 



Other inaccuracies are the value for the melting 

 point of palladium, given as 1950° C. instead of 

 1525° C. + 25, of nickel, given as 1500° C. instead 

 of 7427° C, and of wrought iron, given as 1600° C. 

 instead of 1500° C. 



One rather unfortunate tendency of the work is to 

 deal in a multiplicity of units. There is, for example, 

 no need to speak of " hektowatts," and it is certain 

 that some of the subdivisions of the millimetre dealt 

 with in the chanter on units are only confusing and 

 rarely met with in practical work. Th^n, also, the 

 units' other than metric given in the book as at pre- 

 I 



