CHAPTER VI. 



LAW OF CORRELATION. 



THE external form and general characteristics of 

 an individual, as determined by heredity, are the re- 

 sult, as we have seen, of the prominence of those 

 characters that are made dominant, and the suppres- 

 sion of others which, for the time being, are said to 

 be latent. In the arrangement of these dominant 

 characters in the organization, a principle of develop- 

 ment and suppression appears to prevail, which is 

 recognized by naturalists as the law of correlation. 

 This law may be defined in general terms as follows : 

 Any peculiarity in the development of one organ, or 

 set of organs, is usually accompanied by a correspond- 

 ing modification or suppression of organs belonging 

 to some other part of the system. In this place we 

 shall only notice the relations of this law to heredity, 

 reserving for another chapter its applications in deter- 

 mining internal qualities from peculiarities of external 

 conformation. 



The ^correlated structure of animals enables the 

 comparative anatomist, from the examination of a 

 single tooth, or fragment of bone, to determine not 

 only the class and order to which an animal belongs, 

 but its habits and mode of life, and the character of 



