VIII. 



The Recapitulation Theory in Biology. 



I HAVE read with interest the articles on the above theory by Dr. 

 Hurst and Mr. Bather in Natural Science for March, April, 

 and May. Mr. Bather states that my work has been inspired by the 

 Recapitulation Theory; and Dr. Hurst is pleased to retort that this is 

 a fantastic theory accepted as a creed by myself and others. Now I 

 am not altogether sure that Mr. Bather is absolutely correct in speak- 

 ing of my work as inspired by the Recapitulation Theory ; what I 

 have upheld is a " Law of Earlier Inheritance." That this law, of 

 necessity, leads to a theory of recapitulation is no doubt true ; but it 

 is the law of Earlier Inheritance which has guided my work. Upon 

 this law I have set forth my views, and have shown by comparisons 

 of the ontogeny with the (say, assumed) phylogeny in Ammonites 

 that recapitulation is and can only be imperfect.^ As these views are 

 fully detailed in a paper on " Some Laws of Heredity," ^ I need not 

 go over that ground again. Dr. Hurst will find that I have fully taken 

 into account the similarity of embryos of dissimilar species — which 

 seems to be a stumbling block to his acceptance of Recapitulation. 



I will assume that Dr. Hurst has not read this paper, or any 

 notice of it ; in which case it is curious that, approaching the subject 

 from a totally different point of view, he has defined variation in 

 nearly similar, though wider, terms to what I used some months before.3 



So far I will suppose that Dr. Hurst and myself are practically in 

 agreement ; but it is useless to discuss a question of this kind unless the 

 one knows exactly what the other requires. My object, therefore, is to 

 point out where it seems necessary for Dr. Hurst to amend his statement. 



In page ig8 Dr. Hurst denies any causal relation between 

 ontogeny and phylogeny ; in page 197 he says, " the more the adult 

 structure comes to be unHke the adult structure of the ancestors, the 

 more do the late stages of development undergo a modification of the 

 same kind." By " late stages of development " Dr. Hurst means, 

 I presume, premature development — a point I will notice later. 

 Now, as it stands, the sentence conveys to the mind the idea that the 

 premature stages of an individual become altered in consequence of 

 alteration to the mature stages, which are not formed till later. This 



1 Inf. Ool. Ammonites {Pal. Soc, 1892), part vi., p. 288, footnote 2. 



2 Proceedings Cotteswold N. Club, vol. x., part iii., p. 258, Oct., 1892. 

 Translated into German, forming vol. xviii., series i., of Darwiiiistische Schri/ten, 

 March, 1893. ^Op. cit., p. 261. 



