474 TRANSMISSION 



of its own, and each establishes and maintains, apparently, fairly 

 definite relations to certain of its associates (correlation), while 

 with reference to others it seems indifferent if not independent. 



Individuals inherit differently. All individuals of the same 

 race possess the same characters, but in different proportions, 

 and no two individuals, even from the same parents, are alike. 

 Some portion of this difference is of course due to development 

 according to the conditions of life, yet all evidence goes to show 

 that, after full allowance is made for this factor, natural differ- 

 ences exist that can be due only to inheritance. 



That each individual is in possession of all the characters of 

 the race is evidenced by the fact that his descendants possess 

 them and that he transmits far more characters than are de- 

 veloped sufficiently to be noticeable in his own personality. 



Latent characters. Thus characters may be present, but 

 undeveloped, or " latent." Galton asserts that latent charac- 

 ters are "not very numerous"; 1 but it is certain that many 

 characters may remain undeveloped through life and yet be 

 transmitted perfectly. Familiar examples are the occasional 

 secretion of milk by the male sex, already alluded to, and 

 the transmission of the milking quality by bulls as well as 

 by cows. All things considered, it is safe to say that the visi- 

 ble and fully developed characters of an individual constitute 

 but a small proportion of his real possessions. Especially may 

 this be said of a highly differentiated race. 



Inheritance not limited to sex. It has been a favorite saying 

 that certain characters are transmitted to one sex but not to the 

 other. There is no evidence of any such limitations to inherit- 

 ance. The limitations of sex may and do prevent the develop- 

 ment of many characters that we know to be potentially present, 

 so far as inheritance is concerned, because they can be trans- 

 mitted. In this respect the relation of the male mammal to milk 

 secretion is not different from that of the female that has never 

 yet borne young. The faculty is latent, 2 or undeveloped, in both 



1 Galton, Natural Inheritance, p. 187. 



2 The term " latent " is unfortunate. It conveys too strongly the sense of 

 lurking. "Undeveloped" is the sense that ought to attach to this unfortunate 

 term that has now been used too long to be dislodged. 



