August 14, 1896.] 



SCIENCE. 



179 



and can hardly be said to have advanced 

 beyond the stage which called forth Vol- 

 taire's famous sneer : ' L'etymologie est 

 une science oii les voyelles ne font rien et 

 les consonnes fort pen de chose.' Of the 

 animal pedigrees, now so frequently pro- 

 pounded, few have any better foundation 

 than the guessing etymologies of the last 

 century, and for exactly the same reason. 

 Just as the old etymologists had no test to 

 distinguish a true derivation from a false 

 one, except a likeness in sound and mean- 

 ing in the words compared, so the modern 

 morphologist is yet without any sure test 

 of the relationships of animals, except cer- 

 tain likenesses or unlikeness of structure. 

 How much weight is to be allowed a given 

 similarity, and how far this is offset by a dis- 

 similarity which accompanies it, we have, as 

 yet, few means of determining, and have still 

 to discover those laws of organic change 

 which shall render the same service to mor- 

 phology as Grimm's law has done to the 

 study of the Aryan tongues." 



Philology was raised to the dignity of a 

 true science by the laborious tracing back 

 of modern words, step by step, to their 

 ancient origins, through all their inter- 

 mediate gradations, and sound principles of 

 etymology could not be established until 

 this was done. Morphology must profit by 

 this lesson and must imitate the method of 

 the science of language. Not until many 

 long phylogenetic series have been re- 

 covered, can the law of change be worked 

 out. It is just here that paleontology is 

 fitted to render invaluable services to the 

 common cause. 



As every one is aware, the principal 

 methods of morphological inquiry are com- 

 parative anatomy, embryology and paleon- 

 tology, each of which has its great advan- 

 tages, but accompanied by its own peculiar 

 drawbacks and limitations. Lack of time 

 will prevent any discussion of Bateson's 

 proposed new method for the study of vari- 



ation. I have elsewhere examined that at 

 some length. 



The foundation and corner stone of the 

 whole structure of morphology must ever 

 be comparative anatomy, an accurate knowl- 

 edge of which is indispensable to successful 

 prosecution of the other departments of in- 

 quiry. This method has, in the hands of 

 the masters, registered many great triumphs 

 in the solution of diflacult problems of ho- 

 mology and of the mutual relationships of 

 animal groups. At the present time the 

 tendency is to give more and more weight 

 to its determinations. On the other hand, 

 finality cannot be reached by this method. 

 It suffers from the very significant draw- 

 back of possessing no sure criterion by 

 which to distinguish between those simi- 

 larities of structure which result from actual 

 genetic relationship and those which are 

 due to parallel or convergent development, 

 and thus to determine the taxonomic value 

 of a given likeness or unlikeness. It is an 

 exceedingly common fallacy to assume that, 

 because a number of allied groups display 

 a certain structure, their common ancestor 

 must also have possessed it. This may 

 have been the case, but it is almost as likely 

 not to have been, because the structure in 

 question may have been many times inde- 

 pendently acquired. While the comparative 

 method frequently enables us to discrimi- 

 nate between the two classes of phenom- 

 ena, it generally does not do so, and it never 

 can give entire certainty upon this point. 



On comparing the humerus of the horses 

 with that of the camels, we find in each a 

 characteristic difference from other artio- 

 dactyls and perissodactyls and agreement 

 with each other — a feature which may be 

 described in brief as the duplicity of the 

 bicipital groove and presence of a bicipital 

 tubercle. It is a priori probable that such 

 an isolated resemblance between two widely 

 separated groups is due to convergence, and 

 yet the comparative method can give us no 



