June 2, 19 10] 



NATURE 



595 



iient — Prof. T. W. Bridge — and that it should deal 

 with a subject which he had made peculiarly his 

 own. namely, the air-bladder of fishes. The main 

 purpose of this interesting paper is to consider this 

 remarkable organ, not from the points of view of 

 morphology and function, though these aspects are 

 not neglected, but as the source of isinglass. The 

 author pointed out that, although there are 7000 

 or 8000 species of fishes with air-bladders, few- 

 are utilised for the supply of isinglass, and he sug- 

 gested that the air-bladders of some of our larger 

 British food-fishes, such as the cod, hake, gurnard, 

 &c., might be of value for this purpose. Isinglass is 

 apparently the only product of the animal body which 

 can be used as a clarifying agent in brew-ing opera- 

 tions, and its mode of action does not seem to be at 

 all clearly understood, but it is believed that it depends 

 on the fibrous nature of the substance. The fibres 

 swell out in the liquid, particles become entangled 

 in their meshes, and are carried, with the settling of 

 the isinglass, to the bottom of the barrel. 



There is one other contribution from the pen of 

 the late Prof. Bridge, probably his last published 

 work, on the presence of a false acetabulum in a 

 Bandicoot. Dislocation of the head of the right femur 

 resulted in the formation of a false socket on that side 

 of the pelvic girdle, dorsal to and closely resembling 

 the normal acetabulum, which latter had undergone 

 retrogressive modification as the result of the loss of 

 function. 



Half the remaining papers in this volume are 

 concerned with fishes — Mrs. Merritt Hetwkes records 

 the presence of a vestigial sixth branchial arch in the 

 Heterodontida?, describes the cranial and spinal nerves, 

 the abdominal viscera, and a vestigial seventh bran- 

 chial arch of Chlamydoselachus, and gives a useful 

 account of the theor\^ of nerve components ; Mr. A. D. 

 Imms describes the gill-rakers of the spoonbill, and 

 the oral and phan,-ngeal denticles of Elasmobranchs ; 

 and Mr. R. H. Whitehouse discusses the morphology 

 of caudal fins, directing attention to the effects of 

 specialisation, especially abbreviation, of the axis and 

 restriction of the caudal fin in homocercal tails, and 

 concluding that the present homocercal caudal fin is 

 really a posterior anal which owes its present position 

 to the great abbreviation of the axis coupled with ex- 

 cessive upturning of the end of the chorda. 



There are further contributions from Mr. Imms on 

 Anurida (being his L.M.B.C. memoir on this Collem- 

 l)olan), and oh the occurrence at Port Erin of a 

 -pseudo-scorpion (Obisium miiscorum) in the fissures of 

 rocks in such positions that the specimens had to 

 endure submersion twice daily. The studies also in- 

 clude papers on sex-inheritance in the moth Abraxas 

 grossiilariata and its variety lacticolor, and on animal 

 parthenogenesis, by Mr. L. Doncaster ; on the anatomy 

 of the " green fly " of rose trees by Mr. A. J. Grove, 

 and on the gonadial grooves of Aurelia by Mr. T. 

 ■Goodey. 



The studies bear testimony to the range of view 

 of the late professor and to his stimulating influence 

 •on his pupils. 



NO. 21 18, VOL. S^] 



OUR BOOK SHELF. 



Physiology of the Special Senses. By M. Greenwood, 



Jun. Pp. vii+239. (London : Edward Arnold, 



19 10.) Price 8s. 6d. net. 

 In trite phraseologv*, this book supplies a long-felt 

 want, and supplies it in a manner which is alto- 

 gether commendable. It is elementary, but not so 

 elementary as merely to traverse the same ground as 

 that covered inefficiently in so many text-books. In 

 reading the chapters devoted to the special senses in 

 many text-books of physiology, one feels irresistibly 

 that the author is out of sympathy with the subject. 

 In this book the physiology of the special senses is 

 introduced to the reader with illuminating clearness 

 born of thorough knowledge and judicial discrimina- 

 tion. The requirements of the student are catered for 

 by a teacher who knows how to interest his audience, 

 but at the same time demands an attentive applica- 

 tion of intelligence. Thought is stimulated, and the 

 desire for further knowledge evoked. Each chapter 

 concludes with a short but well-selected bibliography, 

 pointing out the path for further study. 



After an introduction dealing with the laws of 

 Miiller, Weber and Fechner, cutaneous sensation, taste 

 and smell, the sense of position and movement, hear- 

 ing, vision, and the physiology of space come succes- 

 sivelv under review. The work of Head and his col- 

 laborators, Rivers, Sherren, Ham and Thompson, 

 upon protopathic and epicritic sensibility is clearly 

 described, whilst the subsequent researches of Trotter 

 and Davies are discussed and criticised. Taste and 

 smell, the sense of position and movement, and hear- 

 ing are adequately treated, but, as was to be expected, 

 the physiology of vision in its manifold and complex 

 manifestations demands the major part of the book, 

 more than half the pages being devoted to its con- 

 sideration. 



After a chapter on the comparative physiology of 

 vision, retinal processes, electrical, phototropic and 

 chemical responses are dealt with. The student is led 

 on in logical sequence to visual adaptation, entailing 

 a discussion of peripheral vision and total colour- 

 blindness. The chapter on recurrent vision theories 

 of adaptation gives the reader ample food for reflec- 

 tion, and in entering upon the thorny subject of 

 trichromatic vision the author wisely quotes the warn- 

 ing words of Helmholtz : — " The confession of actual 

 doubt is better than the delusion of dogmatic 

 certaint},'. " 



The treatment of colour-vision and colour-blindness 

 is admirable. Expanded and treated more exhaus- 

 tively in the same judicial spirit it might form a 

 valuable corrective to the obsessions which the subject 

 seems almost inevitably to induce. Further chapters 

 are devoted to after images, historical theories of 

 vision, the Young-Helmholtz theor}-, Hering's 

 theor\', and simultaneous contrast. 



Reminiscences of a Strenuous Life. Bv Prof. Edward 

 Hull, F.R.S. Pp. iv+119. (London: Hugh Rees, 

 Ltd., 1910.) Price 45. 6d. net. 

 Though nothing appears in this simple record to 

 justify the adjective in the title, it will afford to many 

 a pleasant reminder of a life still keen and active, yet 

 bridging the years between Thomas Oldham's lec- 

 tures in Dublin and the Darwin celebration of 1909. 

 Dr. Hull originally studied at Trinity College, Dublin, 

 with the view of becoming a clergyman of the 

 Church of Ireland, and it is interesting to note that 

 a course in the Irish language then formed a part 

 of the recognised curriculum. Having, however, 

 been attracted by engineering, he came under Old- 

 ham's influence, and, with his aid, began work on 



