The Theory of Evolution 45 



nent in this connection, yet the theory has claimed an ever 

 increasing number of adherents, until at the present time it 

 is rare to find a biologist who does not accept in one form or 

 another the general principle involved in the theory. The 

 storm of criticism aroused by the publication of Darwin's 

 " Origin of Species," was directed more against the doctrine 

 of evolution than against Darwin's argument for natural se- 

 lection. The ground has been gone over so often that there 

 would be little interest in going over it again. It will be more 

 profitable to turn our attention to the latest attack on the 

 theory from the ranks of the zoologists themselves. 



Fleischmann, in his recent book, " Die Descendenztheorie," 

 has made a new assault on the theory of evolution from the 

 three standpoints of paleontology, comparative anatomy, and 

 embryology. His general method is to try to show that the 

 recognized leaders in these different branches of biology 

 have been led to express essentially different views on 

 the same questions, or rather have compromised the doc- 

 trine by the examples they have given to illustrate it. 

 Fleischmann is fond of bringing together the antiquated 

 and generally exaggerated views of writers like Haeckel, 

 and contrasting them with more recent views on the same 

 subject, without making sufficient allowances for the ad- 

 vances in knowledge that have taken place. He selects 

 from each field a few specific examples, by means of 

 which he illustrates the weakness, and even, as he be- 

 lieves, the falsity of the deductions drawn for the par- 

 ticular case. For example, the plan of structure of the 

 vertebrates is dealt with in the following way : In this 

 group the limbs, consisting typically of a pair of fore- 

 legs and a pair of hind-legs, appear under the form of 

 cylindrical outgrowths of the body.. In the salamander, 

 in the turtle, in the dog, the cylindrical legs, supporting 

 the body and serving to support it above the ground, are 

 used also for progression. The general purpose to which 



