NA TURE 



289 



THURSDAY, JANUARY 24, i895- 



A BAD METHOD IN TEXT-BOOKS. 

 Lehrbuch dcr Verglcichenden Anatomie. Von Arnold 

 Lang, o. Professor der Zoologie und vergleich- 

 Anatomie, Zurich. 4te Abtheilung : Echinodermen 

 und Enteropneusten. (Jena: Fischer, 1894.) 



PROF. ARNOLD LANG completes, by the pub- 

 lication of this fourth part, his treatise on the 

 comparative anatomy of Invertebrata. As the suc- 

 cessive parts of this work have appeared, the author has 

 changed to a considerable degree the limits of space 

 which he appears originally to have contemplated, and 

 has consequently treated those groups reserved for later 

 volumes at greater length than that which he permitted 

 himself to occupy in the first part of the work. We note 

 that he now proposes to rectify this inequality by the 

 production of new editions of the earlier part of the 

 treatise. 



Prof Lang remarks in an interesting "Nachwort," 

 that "man hat es vielfach getadelt " — that is to say, 

 "complaints have been very generally made" — that the 

 names of authors are not cited in the discussions which 

 constitute the text of his work. I confess that I am 

 most emphatically in agreement with those who have 

 i ■"getadelt"; and I do not think that Prof. Arnold Lang's 

 i contention is either correct in itself or sufficient (if it 

 were correct), when he asserts that the book would have 

 been double the size it is, had he given an impartial 

 I account of the historical development of the knowledge 

 ■of the facts which he describes, with reference to the 

 names of the most important authors. There are, it 

 seems to me, three good reasons for adopting the method 

 to which Prof. Lang objects. Firstly, such a method 

 ■(namely, a historical method not carried beyond the cita- 

 tion of the works of the chief contributors to surviving 

 doctrine) is the most natural for the mind of the student 

 to follow, and gives him the truest appreciation of the 

 present condition of knowledge on any topic, and of its 

 probable future development ; secondly, such a citation 

 of the names of really surviving authorities — that is to 

 say, of authors whose work is at this moment admitted as 

 being the original and approved source of observational 

 record, or theoretical conception still holding its ground 

 - is, as a mere mitter of bibliographical reference, of far 

 more service to the student than an indiscriminate list 

 of memoirs at the end of a chapter (such as Prof 

 Lang gives) without any indication of the contents of 

 the memoirs named ; thirdly, that such a citation is the 

 bare justice to his predecessors and contemporaries 

 which every teacher of zoology (or other advancing 

 science) should fee! bound to accord, and should, I ven- 

 ture to say, gladly and scrupulously take trouble to 

 ensure for those whose original work he has appropriated 

 and accepted. 



I confess that 1 feel sensible of something ungenerous 

 and even unfair when I read the long and careful state- 

 ments as to the skeletal and other systems of the Echino- 

 derms (300 piges), illustrated by admirable copies of 

 ■other naturaliits' drawings, made in the present volume 

 by Prof. Lang, without citing in his text a single name 

 NO. 1317, VOL. 51] 



of those to whom he and the world in general are indebted 

 for all this knowledge. After all, it may well be ques- 

 tioned whether any man of science is justified in making 

 statements, even in a text-book, as though he himself had 

 investigated and was responsible for the accuracy of 

 these statements in virtue of his own observations on 

 the objects described, when all the time he is simply 

 stating what this man and that man have seen, and 

 he has not seen, though he omits to mention the name 

 of any of those to whom he is indebted. When 

 such a method is adopted, one is quite unable to dis- 

 tinguish the individual opinions of the author from the 

 mass of second-hand information which he pours out. 

 A very simple introduction of the phrases, '' as was first 

 shown by X," or "according to the observations of Y," 

 or again, " an observation which I can confirm, as it has 

 been called in question," would alter the whole signifi- 

 cance of Prof. Lang's discourse, and make it not only 

 much more valuable, but much more interesting. At the 

 same time, let me hasten to say that every one will at 

 once accept Prof. Lang's statement, that his object in 

 ignoring the names of zoologists has been to secure 

 brevity. My contention is that the end has not 

 justified the means. 



Take, for instance, the so-called "apical" nervous sys- 

 tem of the Crinoids. The discovery of this remarkable 

 and altogether improbable nervous system by that staunch 

 and unwearied naturalist. Dr. W. B. Carpenter, in his old 

 age, is one of the most delightful episodes in the history of 

 comparative anatomy. He made the discovery after he 

 was seventy years of age, and no one believed that his in- 

 terpretation of his observations was correct when he first 

 announced it. Old as he was, he lived to see his discovery 

 confirmed and accepted on all sides. This extraordinary 

 nervous system is described at some length , and explained 

 by figures in Prof. Lang's book ; yet the name of Dr. 

 Carpenter is not once mentioned in connection with it, 

 and the figures given (p. 966) are taken from and 

 ascribed to Beyrich (!) and Carpenter's son Herbert, who 

 merely worked out, long after his father's complete 

 publication, some details of the old man's discover)'. 

 On the other hand, the mere accident that the coeca 

 of the lantern-membrane, discovered by Prof. Charles 

 Stewart in the Cidaridse, have no special name, results 

 in a recognition of his interesting discovery by the title 

 of the " Stewartschen Organen." 



The unsatisfactory character of Prof. Lang's method, 

 if we regard his book as one for reference and assistance 

 in tracing the more recent discoveries, is well exhibited 

 in the section of little more than one page (pp. 1036, 1037) 

 on the axial organ of Echinoderms (dorsal organ, heart, 

 pseudo-heart, renal organ, plastidogenous gland, ovoid 

 gland, lymph gland). Here the space assigned by the 

 author seems to be singularly out of proportion to that 

 given to other topics, and we get not only the very 

 scantiest description of the axial organ in Asterids, 

 Ophiurids, Echinoids, and Crinoids, but no indication or 

 reference luhaUvcr to ampler sources of information. 

 Since this is really one of the critical subjects of recent 

 investigation in Echinoderm anatomy, it is to be regretted 

 that Prof Lang says so little about it. 



Whatever faults one may find with Prof. Lang's book, 

 there is no doubt that it also has merits, and will be 



O 



