;62 



NATURE 



[February 15, 1894 



The rest of Mr. Kew's book is devoted to the dispersal 



of shells by human agency, and to a discussion of the 



claims of certain species to be considered native in Britain. 



This part is very good, and, like therest of thebook,iscom- 



mendably free from bias, though we do not always agree 



with the author's conclusions. Mr. Kew in a future edition 



should add a counterbalancing chapter on human agency 



as preventing the dispersal of snails. We cannot help 



thinking that the making of fences and the extermination 



of the larger mammals in Britain has largely stopped the 



transportation of land-shells. Any one who has noticed 



the masses of earth that adhere to the flanks of an ox 



that has slept in a damp meadow, must realise that in the 



days of the shaggy-haired mammoth, bison, Irish elk, and 



wolf, dispersal both of animals and plants may have been 



far more rapid than at present. Lyell has pointed out that 



seeds may often be carried long distances by a hunted 



animal, and the same reasoning applies to any small 



moUusca or their eggs that may be entangled in the long 



hair. Even the coarsely masticated grass in the paunch 



of a deer or bison torn to pieces by the wolves might 



contain living snails, for many of the dry-soil species 



habitually cling in great profusion to grass stems. 



Migrating animals, especially the bison, may have greatly 



assisted in the carrying of both land and fresh-water shells 



for long distances. 



We must congratulate the author on the publication of 

 this excellent manual. It will undoubtedly lead to the 

 accumulation of numerous observations, and we hope 

 soon to welcome a new edition, in which more ot the 

 suggested modes of dispersal may be confirmed by 

 actually observed cases. We hope also that the publishers 

 will see their way to the inclusion in the International 

 Scientific Series of volumes on the dispersal of other \ 

 groups, for the transportation of species from country to 

 country is certainly a subject that should be fully dealt 

 with in a series claiming to be international. 



Clement Reid. 



OUR BOOK SHELF. 



The Wilder Quarler-Century Book. A Collection of 

 Original Papers, dedicated to Prof. Burt Green Wilder 

 at the close of his twenty-fifth year of service in Cor- 

 nell University (1868-93), by some of his former 

 Students. (Ithaca, N.Y., 1893.) 



Under the above somewhat fanciful title we have a 

 royal octavo volume of just 500 pages, and twenty-eight 

 plates, which contains some fifteen papers written by 

 former pupils of Dr. B. G. Wilder, Professor of 

 Physiology, Vertebrate Zoology, and Neurology in 

 Cornell University, and dedicated to him as a testimonial 

 of the writers' appreciation of his unselfish devotion to 

 the university, and in grateful remembrance of the in- 

 spiration of his teaching and example. Following the 

 practice of some of the German universities, Cornell 

 has been the first among those of the New World to 

 present the teacher with the results of what he has 

 taught ; and the idea seems so commendable that a 

 notice, rather than a criticism, of this volume seems all 

 that IS demanded at our hands. As a frontispiece to the 

 volume there is a portrait of Dr. Wilder, engraved on 

 wood, by John P. Davis, the secretary of the American 

 Society of Wood Engravers, which is an excellent piece 

 of artistic work. A mere enumeration of the contents of 

 the volume must suffice: Dr. D. S. Jordan, on tempera- 

 NO. 1268, VOL. 49] 



ture and vertebrae, a study in evolution, being a discussion 

 of the relations of the numbers of vertebrae among fishes 

 to the temperature of the water and to the character of 

 the struggle for existence ; Susanna P. Gage, on the 

 brain of Dieinyctylus viridescens, from larval to adult 

 life, and comparisons with the brains of Amia and of 

 Petromyzon ; Dr. G. S. Hopkins, on the lymphatics and 

 enteric epithelium of Amia calva; S. H. Gage, on the 

 lake and brook lampreys of New York, especially those 

 of Cayuga and Seneca Lakes ; L. O. Howard, on the 

 correlation of structure and host relation among the 

 Encyrtinae ; J. H. Comstock, evolution and taxonomy, 

 an essay on the application of the theory of natural 

 selection in the classification of animals and plants, 

 illustrated by a study of the evolution of the wings of 

 insects, and by a contribution to the classification of 

 the Lepidoptera ; Dr. E. R.Corson, on the vital equation 

 of the coloured race, and its future in the United States ; 

 Dr. T. Smith, the fermentation tube, with special re- 

 ference to anaerobiosis and gas fermentation production 

 among bacteria; Dr. H. M. Biggs, a bacterial study of 

 acute cerebral and cerebro-spinal lepto-meningitis ; Dr. 

 V. A. Moore, the character of the flagella on the 

 Bacillus cJiolerce suis (Salmon and Smith), B. Coli com- 

 i7iunis (Escherich), and the B. typhi abdominalis 

 (Eberth) ; Dr. W. C. Krauss, muscular atrophy con- 

 sidered as a symptom ; P. A. Fish, on brain preservation, 

 with a rc'suiiu' of some old and new methods ; W. R. 

 Dudley, on the genus Phyllospadix ; Dr. J. C. Branner, 

 observations upon the erosion on the hydrographic 

 basin of the Arkansas River above Little Rock. 



Machine Drawing: By Thomas Jones, M.I.Mech.E., 

 and T. Gilbert Jones, Wh.Sc. (Manchester; John 

 Heywood, 1893.) 

 This book contains properly finished and complete draw- 

 ings of machinery details taken from recent practice, 

 the authors being of the opinion that the best way to 

 encourage the student to make good drawings is to place 

 good ones before him as copies. Exercises are given 

 which require the student to test his power of making 

 original drawings, by deducing from the complete views 

 given, others which are not given. 



One of the authors, being engineering master at the 

 Central Higher Grade Board School, Manchester, has 

 necessarily had much experience in teaching machine 

 drawing, &c., and the present book was designed by 

 him to take the place of the older specimens of draw- 

 ings, with the intention of placing before the student 

 actual mechanical drawings for copies. This is a step in 

 the right direction, for the nearer mechanical drawing, 

 as taught in the technical school, approaches the real 

 thing in the engineer's office, the better it is for the- 

 students. Taken as a whole these drawings represent 

 modern practice, and are good examples. A locomotive 

 coupling-rod is represented on plate xxiv. fitted with a 

 bush keyed in position and retained on the crank pin by 

 a washer and nut of the same diameter as the external , 

 diameter of the bush. Bushes in time always get loose | 

 in the rod, and in this example there is nothing to pre- | 

 vent the rod coming off the bushes and causing an acci- i 

 dent. The nut and washers are screwed on the pin only ; j 

 these ought to be retained in position by a taper or split 

 pin as well. 



The authors give much sensible and good advice on 1 

 the subject of drawing generally, which if carefully fol- ) 

 lowed by the student will make the drawing a creditable j 

 one. The book contains forty plates and many perspec- I 

 tive illustrations ; it is nicely got up, and should prove of j 

 value in our technical schools and colleges. 

 Hydrostatics atid Pneumatics. By R. H. Pinkerton, B.A. ' 



(London : Blackie & Son, Ltd., 1893.) 

 The application and non-application of the integral 

 calculus seems to be a bar which divides many text-books 



