NATURE 



265 



THURSDAY, JULY 18, 1907 



;4Ar INTRODUCTION TO THE COMPARATIVE 

 ANATOMY OF VERTEBRATES. 



Einfuhruwg in die Vergleichendc Anatomic dcr Wirbcl- 

 ticrc. Bv Prof. Robert ^A'icdersheim. Pp. xxii+471; 

 illustrati-d. (Jena : Gustav Fischer, 1907.) Price 

 1 1 marks. 



THE fatalities which may overtake standard text- 

 bool<s are numerous and complex in their action, 

 but on the whole, overgfrowth, the result of repeated 

 editions, is one of the commonest causes of extinction. 

 With the incorporation of new material in each edition, 

 the scientific merit of a work may rise, but unfortun- 

 ately its commercial value will certainly decline; from 

 an examination book with a wide circulation amonarst 

 students it becomes a reference book, used only by 

 experts. This is a difficulty which faces every 

 author in the preparation of a new edition of a stan- 

 dard text-book ; he may do his duty at the expense of 

 circulation, or he may throw overboard older work to 

 make room for the new, and thus maintain or even 

 increase the circulation, or lie may do as Prof. Wieder- 

 sheim has done — allow the work to increase with the 

 growth of knowledge, and issue another book alto- 

 gether, into which are condensed the merits and essen- 

 tials of the older work. 



The volume under review is a condensation of Prof. 

 Wiedersheim's well-known text-book on comparative 

 anatom)'. It will be widely used, no doubt, by medical 

 and by science students in Germany, but it will also 

 prove of the greatest service to those who wish to 

 obtain a summary of our modern knowledge of this 

 subject. The author has the incomparable advantage 

 of a first-hand knowledge of the whole length and 

 breadth of vertebrate anatomy; as colleagues and 

 advisers in the University of Freiburg he has Gaupp, 

 Keibel, and E. Fischer, each eminent in his own field 

 of work. He possesses a simple, easy diction, a judi- 

 cious eye for the selection of his facts, and a very open 

 mind. His attitude perhaps is too cautious, too non- 

 committal ; difficult and unsettled problems are simply 

 mentioned or brushed aside. 



It is a curious fact that no British anatomist has 

 ever produced a systematic treatise on comparative 

 anatomy of the t}'pe so common in Germany — the type 

 best represented bv the works of Gegenbaur and 

 Wiedersheim. Huxlev's classical work on vertebrate 

 comparative anatomy is arranged on quite different 

 lines ; there the anatomical facts are so grouped as to 

 throw light on the relationship of one class of animals 

 to another; clearly, in Huxley's opinion, the chief 

 object of the anatomist is to ascertain the evolutionary 

 history of the animal, whereas the German anatomist 

 seeks the evolutionarv history of the organ. English 

 anatomists set their facts under a zoological classifica- 

 tion, whereas, in the book under review, the classifica- 

 tion is strictly anatomical. Prof. Wiedersheim may 

 make incidental allusions to the bearing of a fact on 

 the position of one group of animals to another — such 

 as the impossibility of deriving the mammalian lung 

 NO. 1968, VOL. 76] 



from the reptilian — but such allusions are few and far 

 between. Clearly he has no immediate object in view 

 saving that of bringing together in an orderly ar- 

 rangement all that is known of the form and variation 

 of each organ. Strictly speaking, the classification 

 adopted in German works on comparative anatomy is 

 essentially physiological; the structures subserving cir- 

 culation are dealt with in one chapter, those of respir- 

 ation in another, and it may be at once admitted that 

 this method of classification has an overwhelming 

 advantage over any other. Yet such a treatise is the 

 last one in the world one would consult for physi- 

 ological information, because the correlationship be- 

 tween function and form has never appealed very 

 strongly to the German anatomist. .\s knowledge in- 

 creases, it becomes more and more certain that the key 

 to comparative anatomy is comparative physiology— a 

 subject yet in its infancy. 



This statement, however, is less true of Prof. 

 Wiedersheim than of his compeers ; one rejoices to 

 see occasional allusion to function in his work ; he 

 rightly describes the functional significance of the air 

 sacs attached to the lungs of birds ; his allusion to 

 the function of the accessory sexual organs will prob- 

 ably assist the student to understand their structure 

 and relationship; mention is made of the effects of the 

 substance secreted by the suprarenal body in raising 

 the arterial blood-pressure, although nothing is said 

 of its equally important action on the musculature of 

 the alimentary canal. There is a frank, engaging 

 honesty in the manner with which Prof. Wiedersheim 

 deals with structures of obscure meaning. .As regards 

 the descent of the testicle, he says it is a " schwer 

 crkl.'irbaro Vorgang " ; unlike Metschnikoff, he does not 

 conclude that the hymen at the entrance of the vagina 

 has neither function nor meaning, because in the pre- 

 sent state of our ignorance regarding sexual organs 

 generally we have not as yet discovered any function 

 or meaning attached to it. He frankly admits that 

 the significance of the abdominal pores is unknown. 

 On the other hand, he concludes that the lobu- 

 lation of the lung has no physiological significance — an 

 inference which will not be supported by a closer 

 knowledge of the mechanism of respiration. 



There are certain minor blemishes in this work. 

 The index is not nearly full enough. For instance, on 

 taking the book up for the first time, the reviewer 

 wished to ascertain v.-hat was taught regarding the 

 fate of the cloaca in higher mammals, but found no 

 reference to that structure in the index. But in the 

 text he discovered, from incidental remarks rather than 

 from any special description, that Prof. ^Viedersheim 

 regards the anus of the higher mammals as the cloacal 

 orifice, and that the urogenital aperture is a new open- 

 ing. The research of Dr. F. Wood Jones leads to a 

 diametrically opposite conclusion, namely, that the 

 urogenital orifice is the cloacal orifice, and that the 

 anus is a new opening, and hence the frequent occur- 

 rence of atresia ani in children. There are other state- 

 ments, too, with which English anatomists will not 

 agree, such as those regarding the nature of the 

 sternum, the origin and nature of the temporo-maxil- 

 lary joint, the origin and nature of the diaphragm, 



N 



