30 



KNOWLEDGE. 



[January 1, 1897. 



The Evolution of Bird Song. By Charles A. Witchell. 

 (A. ct C. Black.) 5s. For the last ten years or more Mr. 

 Witchell has been studymg bird song, and the present 

 book is the result of his work. We must at the outset 

 heartily congratulate and thank the author for this very 

 valuable addition to ornithological literature. The facts 

 related in the book before us could only have been collected 

 by one who was a keen observer and withal a skilled musician, 

 and we are sure that a number of the author's observations 

 will be new to most ornithologists, and will delight them 

 and all who are interested in our birds. Mr. Witchell 

 puts forward a number of theories in relation to the origin 

 and evolution of bird song. Some of these are plausible 

 enough, and most deserve consideration. We think, how- 

 ever, that the author has overstepped the bounds of com- 

 mon sense in some instances, as, for example, when he 

 leads us to infer that the origin of the landrail's " creaking" 

 note is the imitation of the soimd produced by cattle 

 feeding. Some very startling facts concerning the power 

 of mimicry in certain birds are brought out at the end of 

 Chapter IX. For instance, about seventy thrushes under 

 observation were heard, in all, to imitate the songs or call 

 notes of no fewer than twenty-nine different species of 

 birds. The robin, skylark, starling, sedge warbler, and 

 other birds appear also to mimic to a surprising degree. 

 A>'e have all noticed, on occasions, marked instances of 

 mimicry in the notes of different birds, but the imitations 

 here described are often imperfect and mingled with the 

 bird's usual song. The detection of this class of imitation 

 is by no means within the reach of all : it requires a listener 

 who possesses, besides a very accurate and retentive 

 memory for sounds, a trained ear. The last chapter in 

 the book is devoted to the music of bird song, and an 

 appendix is added containing several songs written in 

 musical notation. Altogether Mr. Witchell's book is of 

 great value, for very little has been written of the songs of 

 buds, and never before has the subject been treated in such 

 an exhaustive and masterly fashion. 



Physies for Students of Medicine. By Alfred Daniell, M.A., 

 LL.B., D.Sc. (Macm'dlan.) Illustrated. 4s. 6d. Partly 

 through the pioneer work of Dr. Daniell in the Edinburgh 

 School of Jlediciue, physics is now part of the extended 

 course of professional study regulated by the General 

 Medical Council. The recognition of the subject was an 

 act of wisdom, for physics is the only sound foundation for 

 scientific knowledge, and is as essential to students of 

 medicine as to students of engineering. To provide the 

 former class with a manual on physical principles, with 

 special reference to the applications of these principles met 

 with in medical science, this book has been written. The 

 result is a fairly satisfactory course of general physics — 

 rather diffuse, perhaps, in parts, but one which will interest 

 and be of service to every practitioner, and which every 

 medical student would do well to follow, if he can find 

 time. How very helpful a knowledge of physics is to 

 medical men may be gathered fi-om the work that has been 

 done this year in Rontgen photography. Practitioners 

 with such a foundation have been able to apply at once 

 their knowledge, while those who are deficient in that 

 regard are mourning that the subject was not included in 

 their studies. Many other instances might be cited, but 

 we believe it is now generally agreed that physics should 

 form part of the professional curriculum ; and if there be 

 any who doubt whether its bearings upon medicine are 

 real, they have only to glance through this book to be 

 convinced of their error. One blemish, to which attention 

 mast be drawn, is the absence of an index. 



Te.vt Book of Zoology. By Dr. J. E. V. Boas. Trans- 

 lated by J. W. Kirkaldy and E. C. Pollard, B.Sc. 

 (Sampson Low). Illustrated. This is an English trans- 

 lation of a work which has appeared in two Danish and 

 two German editions. It is intended primarily to assist 

 beginners in the study of zoology. The book is divided 

 into a general part, treating of the structure and history 

 of animals as a whole, and a special part, treating of the 

 anatomy and shortly of the habits of different orders of 

 animals. Lists are also added of the more important 

 forms of the fauna of the British Isles. The anatomical 

 portions of the book are excellent and well helped out 

 by the numerous illustrations. A glossary of the scientific 

 terms used would, however, have been a valuable 

 addition for the beginner. It would have been better, 

 we think, to have left out the lists of fauna, since they 

 are incomplete. Creatures rare in this country have a 

 place in the lists while others more common are left out, 

 and the lists are thus of very little value. The short 

 reviews of the habits of the animals are also by no means 

 valuable, since they are not altogether correct. For 

 instance, we notice several incorrect statements with 

 regard to the migration of birds. For these reasons we 

 can only recommend the book as an excellent and valuable 

 treatise on zoological anatomy. 



Left Half of Skull of Bua Constriftor. 

 (From "Text Book of Zoolog-j-.") 



A DictioiKiry of Chcinical SDlubilities, Inorijanic. By 

 Arthur Messinger Comey, Ph.D. (Macmillan.) 1.3s. A 

 chemical library will now not be complete without this 

 monumental work on the solubility of chemical substances, 

 and every practical chemist should endeavour to obtain it. 

 The labour involved in the production of such a dictionary, 

 containing data obtained by investigators in many parts 

 of the world, must have been immense. All analyzed 

 inorganic substances are included, the solubility in water 

 being first given, then the specific gravities of the aqueous 

 solutions, and the boiling-points, and, following this, the 

 solubility of the substance in other solvents. The arrange- 

 ment of chemical compounds in alphabetical order was a 

 difficult task, but an intelligent plan has been followed, 

 and cross references are used to obviate to some extent 

 the confusion arising from the want of uniformity in 

 chemical nomenclature. Chemists are thus provided with a 

 volume capable of furnishing them with the results of all 

 important researches on solubility, arranged in a form 

 for ready reference. The great disparity among the sub- 

 stances with which the chemist has to deal, as regards 

 the amount any solvent will take up, is a matter altogether 

 too much for the memory, and it strikes us that students 

 generally, and analytical chemists in particular, will heartUy 

 welcome the volume ; and we trust that it will meet with 

 that best evidence of appreciation — a large circulation. 



