575. 184 



I 



IV 



The Species, the Sex, and the Individual x 



N investigating the evolution of animal structure we have to 

 consider not merely the features which distinguish species and 

 groups of species from one another, but the difference between dis- 

 tinct types within the same species, and the changes which the 

 individual passes through in the course of its life. The selection 

 doctrine is held by its adherents to afford an explanation of the 

 facts in all three of these divisions, but no one has hitherto pointed 

 out the close similarity between the phenomena in the three cases, 

 and attempted to prove that the principles he adopts are really 

 applicable in detail to all of them. Examples of the differences of 

 structure by which animals are classified are familiar to every one ; 

 the remarkable differences between male and female in the same 

 species of bird, such as the peacock or pheasant, illustrate the 

 second class of facts ; and the differences between the tadpole and 

 the frog, the caterpillar and the butterfly, illustrate the third. 



Selection in nature can only mean the survival of an individual 

 by virtue of some useful peculiarity in its structure, and selection as 

 a theory of evolution can only be applicable to structural features 

 which are of some use to the individual, enabling it either to obtain 

 food or shelter, to escape enemies and natural dangers, or to repro- 

 duce its kind. Hence if the selection doctrine is true, everything in 

 the structure of animals must be adapted to some useful end, must 

 be an adaptation — or it must be the physiological corollary of an 

 adaptive structure, must be correlated with some useful variation. 



1 With reference to this paper, Mr Cunningham has given us the following infor- 

 mation, which we have verified. The paper was written at the beginning of 1897, and 

 after some time was submitted to the Zoological Society, but not accepted, even for 

 reading, on the ground that the Society did not usually publish papers of a theoretical 

 and controversial character. The manuscript was then sent to the Linnean Society, 

 where it was read on May 6th of the present year, and a brief description of it was 

 published in the report of the meeting in the Athenaeum and in Nature. But this 

 Society also refused to publish the complete paper, the alleged reason being the pressure 

 of other papers and illustrations. It is due to Mr Cunningham that these facts should 

 be known, for on June 7th, 1898, there was read before the Zoological Society a paper 

 by Mr L. W. Wiglesworth, containing conclusions as to sexual dimorphism very similar 

 to those of the present paper. In particular, as the published abstracts show, the 

 author maintained that secondary sexual characters in birds were due to the stimulation 

 of parts through use, or external violence, or irritation. 



So much for Mr Cunningham's title to priority. As for the refusal to publish his 

 paper, we understand that the Zoological Society has equally refused that favour to 

 Mr Wiglesworth, although he was more fortunate in having his views placed before a 

 meeting, and published in abstract. There is a general feeling among those who hold 

 views opposed to the current strictly Darwinian notions that they cannot get fair play 

 from our learned societies. It is a pity that they should be able to adduce so many 

 facts in support of this opinion, however erroneous the opinion itself may be. — 

 Ed., Nat. Sc, I. 



