144 



NA TURE 



\_June 12, 1884 



become comparative anatomists, but only wish to gain a 

 little knowledge of Vertebrate anatomy. It is not an easy 

 matter, for instance, for a beginner to dissect out the 

 nerves of the head and neck in so small a mammal as 

 the rat, and even the less delicate dissections can be done 

 much more satisfactorily on a larger animal. 



The directions for examination and dissection are clear, 

 but scarcely full enough in some places. The methods 

 given as regards the vascular system, for instance, are 

 somewhat meagre, and the muscles are not touched upon 

 at all. The woodcuts, which illustrate the skull only, are 

 rough, and we fail to see much advantage in giving figures 

 of the skull when the soft parts — illustrations of which are 

 so much more required by the student — are neglected. 



It would perhaps have been as well to omit the question 

 as to the homology of the malleus and incus, given on the 

 first page, as recent researches seem to throw so much 

 doubt on this point. 



Apart from the defects to which we have called atten- 

 tion, the book is well arranged, and any one wishing to 

 learn from it how to dissect a Rodent will be greatly helped 

 by its systematic directions and accurate descriptions. 



A Course of Instruction in Zootomy ( Vcrtebrata). By T. 



Jeffrey Parker, B.Sc, Professor of Biology in the 



University of Otago. (London : Macmillan and Co., 



1884.) 

 ALTHOUGH the study of biology has advanced very 

 rapidly of late years, there is still a great want of really 

 good text-books in several of its branches. The volume 

 before us, which forms the latest addition to the excellent 

 series of " Manuals for Students," is an attempt to fill up 

 one of the most patent of these gaps, and teachers and 

 students of morphology have alike reason to be grateful to 

 Prof. Parker for the manner in which he has performed 

 his work. 



The book consists of a short introduction on the methods 

 of dissection, injection, and preservation of specimens, 

 followed by a series of descriptions of certain typical 

 Vertebrates, with practical directions for their examination 

 by dissection or otherwise. The types described are the 

 lamprey, skate, cod, lizard, pigeon, and rabbit, and have 

 been chosen partly from their intrinsic importance, and 

 partly because they "are mostly such as can be readily- 

 obtained at any time of year." 



The selection of animals is a judicious one, though we 

 should like to have seen Amphioxus included in the list ; 

 the descriptions are clear and accurate, and the practical 

 directions good. The book is of convenient size, well 

 printed, and admirably illustrated by a series of upwards 

 of seventy figures, which, with very few exceptions, are 

 original. Many of these figures, notably those of the 

 lamprey and those of the nervous and vascular systems 

 throughout the book, are of unusual excellence, and both 

 author and publishers deserve much credit for having so 

 full;- recognised the necessity of providing new illustra- 

 tions in place of the old worn-out and often incorrect ones 

 that have disgraced our zoological books for so many 

 years. A few of the figures might with advantage be 

 rather larger and more diagrammatic. 



While freely and gratefully acknowledging the merits 

 of the book, which are such as to insure its adoption at 

 once in all morphological laboratories, there are certain 

 features which we think should not escape criticism. 

 Thus the general arrangement of the book might easily 

 be improved : the " indented " paragraphs will certainly 

 be taken for minor rather than major subdivisions ; the 

 system of numbering the paragraphs does not appear to 

 us to serve any useful end, and the repetition of the title 

 of the book on every alternate page is simply throwing 

 away a valuable opportunity of facilitating reference. 



A far more serious objection, however, is the very small 

 allowance of that " salt of morphological ideas " which 

 Prof. Parker extols in his preface but almost entirely 



omits to supply us with in the book itself. Thus, although 

 the several types selected are arranged in a progressive 

 series, there is practically no attempt made to compare 

 them with one another, or to direct the student's atten- 

 tion to the modifications undergone by the various organs 

 in advancing from generalised to more specialised types. 

 Again, it is surely a mistake to describe the bones of the 

 skull one by one, without any reference to their positions 

 as regards the morphological elements of which the skull 

 consists, or even the distinction between cartilage bones 

 and membrane bones ; and the same objection applies 

 with especial force to the description of the urinary 

 organs. 



However, in thus criticising what appears to us its 

 weak side, we are fully aware that we are finding fault 

 with the conceptions which Prof. Parker has had of the 

 type of book wanted rather than with the manner in 

 which he has carried out his own ideas on the subject. As 

 a practical laboratory guide, the " Course of Instruction 

 in Zootomy " is a valuable addition to zoological literature, 

 and one which will certainly meet with ready and large 

 acceptance. A. M. M. 



Van Nostrand's Science Series. Dynamic Electricity. 



By J. Hopkinson, J. N. Shoolbred, and R. E. Day 



(New York : Van Nostrand, 1884.) 

 Dynamo-Electric Machinery. By Prof. Silvanus P. 



Thompson. (New York : Van Nostrand, 1884.) 



These latest additions to Van Nostrand's "Science Series" 

 are reprints of pamphlets published in England. The 

 first of the volumes contains a lecture by Dr. Hopkinson, 

 which originally formed one of a series delivered at the 

 Institution of Civil Engineers a year ago; a paper by 

 Mr. Shoolbred, also delivered last year and a little work 

 on electric calculations, drawn up by Mr. Day for the 

 evening science classes at King's College, published 

 in 1882 by Messrs. Macmillan and Co. For the title 

 '• Dynamic-Electricity," the American publishers of this 

 medley are alone responsible. The other volume is a 

 reprint of Prof. Thompson's Cantor Lectures, with an 

 introduction by Mr. F. L. Pope. Mr. Pope's idea of 

 editing appears to be to reprint baldly from the unrevised 

 English issue, and to foist into the book two or three 

 large unexplained diagrams of Edison's and Weston's 

 forms of dynamo. We cannot' congratulate either the 

 authors or the publishers on the issue of these unauthor- 

 ised editions. 



The Principles and Practice of Electric Lighting. By 

 Alan A. Campbell Swinton. Pp. 172. (London : 

 Longmans, Green, and Co., 1884.) 

 THIS is a handy and well-written account of the chief 

 kinds of machines and lamps used in electric lighting ; 

 perhaps the best of the numerous small works lately pub- 

 lished on the subject. It is full of information and in 

 almost every respect up to date, though the chapter on 

 the cost of electric lighting is already more or less put 

 out of date by the progress of invention. The author 

 writes impartially and agreeably. He should not call the 

 " watt " a unit of energv. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of rejected manuscripts. 

 No notice is taken of anonymous communications. 



\TK.' Editor urgently requests correspondents to keep their letttrs 

 as short as possible. The pressure on his space is so great 

 that it is impossible otherwise to insure the appearance even 

 of communications containing interesting and novel facts.~\ 



The Rings of Saturn 



I.N the interesting account of the observations of Messrs. Henry 

 on the rings of Saturn (Nature, May 29, p. 105) they seem to 



