HEREDITY; ITS MEANING AND INFLUENCE 227 



on the Houdan breed of chickens. This number of toes com- 

 monly occurs on all good specimens of this variety of French 

 fowls, although four is the usual number with most other 

 breeds. 



Latent hereditary characters exist in all animal life. By 

 this is meant characteristics that are not visible in any form 

 in one or more generations, yet have occurred in the past, a*id 

 may again appear at some time in future. During the past, 

 students of heredity have called such occurrences "atavism/' 

 while stockmen have been in the habit of referring to them as 

 "throwing back," or "breeding back." For example, we 

 have a case of a family of Aberdeen Angus cattle, which is a 

 black breed. Very unexpectedly a red calf is dropped in a 

 herd where not a red animal has been known. Yet a care- 

 ful study of the history of this herd will show that at a pre- 

 vious period there was a red ancestor. This red color 

 was really hereditary, but lay dormant, or latent, as it is 

 termed, for some generations, and then cropped out. The 

 stockman now calls this a "sport." Some scientists speak 

 of it as "mutation." The important point, however, is that 

 this character really was inherited from generation to gen- 

 eration, but did not appear until certain conditions were 

 favorable. Many similar cases might be cited that have 

 caused much comment among stockmen. In this connec- 

 tion, it maybe noted that mutation occurs less frequently with 

 old, well-established breeds than with those not so old, and 

 less under natural than under artificial conditions. It is also 

 important to remember that sometimes mutation results in 

 valuable variations from the parent type. Instances have oc- 

 curred where intelligent breeders have recognized the value of 

 such a "sport," and have succeeded in reproducing it through 

 successive generations, until it became a fixed breed feature. 

 More than one hornless breed of cattle and sheep have been 



