April 30, 1903 J 



NA TURE 



60 t 



that all energy is not equally valuable; thus, in an 

 ordinary gas engine cycle, or that of the Diesel engine, 

 let him assume that when energy has been given up 

 to a crank shaft, and we now expend it in compressing 

 the stuff in a pump, that each unit of it is five or ten 

 times as valuable as mere heat energy; it is astonish- 

 ing how much clearer his notions become concerning 

 real practical efficiency of an engine. He is getting 

 acquainted with the fact that all the problems of the 

 engineer are much more complicated than those of the 

 physicist or mathematician. John Perry. 



VERTEBRATE MORPHOLOGY. 

 V er gleichende Anatomie der Wirbelthiere, mil Bertick- 

 sichtigung der Wirbellosen. Von Carl Gegenbaur. 

 Vol. ii. Pp. viii + 696. (Leipzig : Engelmann, 

 1901.) Price 205. 



THE aged master and founder of modern com- 

 parative anatomy has completed his life's task, 

 and he has retired from the busy world. The results 

 of half a century's active research and incessant 

 thought are embodied in his " Yergleichende 

 Anatomie der Wirbelthiere," of which the second 

 volume deals with the alimentary and respiratory, 

 vascular and urinogenital organs. The plan of the 

 work now needs no further comment j 1 it is the same 

 as that of the first volume. Short, extremely con- 

 densed accounts of invertebrate conditions form a 

 kind of introduction to each chapter, which then deals 

 with the Vertebrata to a very full extent, certainly 

 much more fully than any other general and com- 

 prehensive book. 



On the whole, the present volume is more up-to- 

 date. Naturally so, since the bulk of it has been 

 written within the last few years, and the author 

 was able to dismiss for ever from his mind the vast 

 amount of matter embodied in the first volume. The 

 whole stupendous work, about 1500 closely printed 

 pages and nearly 1000 text-figures, will give an ever- 

 lasting impetus to vertebrate morphology. Not only 

 is there deposited in it an enormous amount of ana- 

 tomical descriptive detail, not only is it full of grandly 

 conceived ideas, but new lines of further inquiry are 

 laid down plainly, with cautioning against lurking 

 pitfalls. It contains all the features of a text-book in 

 the true sense of the word. It is a guide how to 

 study morphology. And still this grand work, 

 although hailed with delight on its first appearance, 

 is not exactly liked or loved. On the contrary, many 

 of its readers are disappointed. Those who expected 

 that the book would be a revelation of the whole of 

 animal morphology would do well to take to heart 

 the author's repeatedly emphasised confession, " dass 

 wir in den meisten Fragen erst am Anfang der 

 Erkenntniss stehen." We, who know little, de- 

 mand a final solution, where the master himself, after 

 his own dissections and having criticised the conflict- 

 ing statements of other workers, is satisfied with 

 opening out entirely new vistas which widen the 

 problem. Examples of this are the chapters dealing 

 with the tongue, palate and epiglottis, wherein are 



1 See review of vol. i. , Naturf, December, 1898. 



I748, VOL. 67J 



embodied some of the author's latest original re- 

 searches. 



But there are several drawbacks which seriouslv 

 detract from the value of the book as a readilv 

 accessible source of information ; it is so difficult to 

 understand. Every great writer has his own style, 

 and that of our author is involved and heavy ; there 

 are hundreds of sentences the deep and sound sense 

 of which does not reveal itself without much painful 

 interpretation. This is felt and frequently admitted' 

 also in Germany. One of his foremost disciples, how- 

 ever, has written an indignant protest against this 

 charge; the apologist points out that the subject- 

 matter itself is difficult, that such a text-book must 

 necessarily stand on another level than a novel, and 

 that Goethe or Kant are likewise not always easy 

 reading, &c. ! Well, there are, and will be, many 

 good morphologists and German scholars who will 

 misunderstand our author, and that through no fault 

 of their own. However serious and annoying, this 

 defect of the book is a matter of form. 



A much graver consideration is the following. The 

 author begins a chapter with a continuous, needless 

 to say logically coherent exposition of the structure, 

 modifications, the phylo- and ontogenetic develop- 

 ment of certain organs, and his own leading view 

 appears clear and convincing until, without warning, 

 he contradicts himself in what he has iaid down pre- 

 viously, perhaps in some other chapter. Or worse 

 still, there follow long passages in small print con- 

 taining another hypothesis or new facts the merits 

 of which are put so forcibly that the reader cannot 

 doubt that this must, after all, be the view preferred 

 by the author. In many of these cases only one inter- 

 pretation can be right, but the text goes on as if no 

 amendment had been carried. Frequently this up- 

 setting mode of treatment is obviously due to more 

 recent additions or interpolations. Of course, a fair- 

 minded author gives every tenable hypothesis, and if 

 he then states that the solution is not yet final, no 

 more remains to be said. This our author does often, 

 even as a rule, but not always, and, therefore, the 

 exceptions are all the more jarring. Jnrare in verba 

 magistri may be a sign of unscientific weakness or 

 laziness, but we have a right to learn the views of 

 an acknowledged master. 



But let us proceed from generalisations to crucial 

 points. 



Origin oj Vertebrata. — The transformation of the 

 anterior cephalic portion of the alimentary canal into 

 a respiratory chamber is predominant in, and typical 

 of, the Vertebrata. Resemblances in the formation of 

 such a chamber, first and faintly indicated in Cephalo- 

 discu-., carried further in Enteropneusta and Tuni- 

 cata, do not mean near relationship with the Verte- 

 brata. Direct transitional stages are still unknown, 

 perhaps because the creatures concerned have died 

 out. Mouth and arms being secondary features in- 

 dicate that the Vertebrata have a long ancestral 

 history. Although Amphioxus resembles Tunicates in 

 many respects (respiratory chamber, peribranchial 

 cavity, hypophysis, &c), the metamerism of its body 

 is a feature of such importance that it forbids any 



