VARIATION 1003 



as in times past there are endless records, among which Orni- 

 thology has its full share,^ of individual irregularities of all sorts, 

 from those which are to be entitled Monstrosities (p. 587) down 

 to the abnormal colouring of a single feather; but no considerable 

 approach has been made to the methodizing of the different observa- 

 tions since the remarkable essays published in 1871 and 1872 by Mr. 

 J. A. Allen,^ which naturally attracted the attention of Mr. Wallace, 

 who (Daj-winism, chap, iii.) by means of a series of diagrams reduced 

 to a concrete and convenient form some of the elaborate tables of 

 measurements, for, as treated by the author, they are not very easily 

 mastered. Few, if any other writers, however, have availed them- 

 selves of the vast store of statistics collected with enormous toil by 

 Mr. Allen, and hence the puljlication of other similar series has 

 unhappily been discouraged. Every one knows the use which has 

 been made of facts like these, but the study of Variation has 

 perhaps suffered from the way in which it has been connected with 

 theories of Evolution instead of being pursued for its o^vn sake. 

 Whether those theories be true or not, the existence of Variation is 

 undoubted, and it behoves ornithologists among other naturalists to 

 learn all they can of its facts apart from any speculation that may 

 be raised upon them. Many persons regard Variation as being so 

 much due to domestication that they are apt to overlook the extent 

 to Avhich wild creatures vary. It would be almost safe to assert 

 that no two creatures are ever produced which are absolutely alike, 

 however hard it may be for any one to define the diflference 

 between them ; but it may be positively stated as the result of con- 

 siderable experience in ornithology that the greater the number of 

 individuals that are closely examined the more they are found to 

 differ. ^ The diflferences may be minute, but differences they are, and 



Species often assumes some of the characters of an allied Species, or 

 reverts to some of the characters of an early progenitor {op. dt. 

 chap. v.). 

 Several modifications of the above statements seem requisite. 

 1 With Ornithology rests perhaps the honour of producing the earliest 

 treatise on part, at least, of the subject, that by Gloger before cited (Geo- 

 graphical Distribution, p. 343). 



^ To these reference has been already made (p. 343, note 2), An apprecia- 

 tive analysis of the first was given in The Zoological Record (viii. pp. 24, 25), 

 and a critical notice in The Ibis (1872, pp. 189-191). Mr. Ridgway followed 

 with some good observations {Am. Journ. Sc. ser. 3, iv. pp. 454-460, v. pp. 

 39-44), which led to the criticism of Prof. Coues {Am. Nat. 1873, pp. 415- 

 418), and a rejoinder by the author {torn. cit. pp. 548-555). 



^ As an instance 1 may refer to the experience gained by the study of an 

 enormous series of bones of the Solitaire (p. 887), not one of which but was 

 liable to greater or less individual Variation of some kind or other. This was 

 not confined to absolute size, but extended to the relative proportion of divers 

 parts of the bones, to processes or depressions upon them commonly held to be 



