BIOLOGICAL LECTURES. 



of value by which to estimate their relative probability. The 

 truth is that the search after suggestive working hypotheses 

 in embryological morphology has too often led to a wild 

 speculation unworthy of the name of science ; and it would 

 be small wonder if the modern student, especially after a 

 training in the methods of more exact sciences, should regard 

 the whole phylogenetic aspect of morphology as a kind of 

 speculative pedantry unworthy of serious attention. There 

 can be no doubt, I think, that this state of things is leading 

 to a distaste for morphological investigation of the type repre- 

 sented, for instance, by Balfour and his school, while the bril- 

 liant discoveries of the cytologists and experimentalists, supple- 

 mented by speculations of the Weismannian type, have set up 

 a new tendency that gathers in force from day to day. 



No candid morphologist can deny that the responsibility for 

 the present degradation of pure morphology must on the whole 

 be laid at the door of speculative embryology, and is the result 

 of too exclusive and undiscriminating a faith in the embryo- 

 logical criterion of homology and the recapitulation theory. It 

 is no wonder that a strong reaction against that theory has set 

 in, that faith in the embryological record is giving way to 

 skepticism and indifference. There is a strong suspicion that 

 the embryological method has somehow failed, and there are 

 even some morphologists who seem almost ready to abandon the 

 entire recapitulation theory. That theory has always had its 

 critics, but the present movement against it may conveniently 

 be dated from Gegenbaur's paper on " Ontogeny and Anatomy," 

 published five years since. In a very moderate and reasonable 

 spirit the author protests against too exclusive a faith in the 

 embryological record, insisting that ontogeny is not the exclu- 

 sive or even the main source of evidence regarding descent. 

 " But if we are compelled to admit that cenogenetic characters 

 are intermingled with palingenetic, then we cannot regard 

 ontogeny as a pure source of evidence regarding phyletic 

 relationships. Ontogeny, accordingly, becomes a field in which 

 an active imagination may have full scope for its dangerous 

 play, but in which positive results are by no means everywhere 

 to be attained. To attain such results the palingenetic and 



