220 INBREEDING AND OUTBREEDING 



sive. The mule hybrid is a remarkable example of the practical ad- 

 vantages which follow a particular cross. This animal is more hardy 

 and enduring than either parent. As compared with the horse, the mule 

 is longer lived, less subject to disease or injury, and more efficient in 

 the use of food. The mule can be safely put to work at a younger 

 age, will thrive on coarser feed, and seems to be much better able to 

 avoid many dangers which menace the usefulness of the horse. The 

 mule will perform more arduous labor on less food. The mule will 

 endure the heat of southern latitudes more successfully than the horse 

 and is therefore a more popular draft animal in the South. 



Other first generation crosses among animals, which 

 are not sterile like the mule, have good qualities and are 

 well known. Youatt, early in the nineteenth century, 

 stated that crosses between the English and Chinese 

 breeds of swine were frequently made, and that in Ger- 

 many the native breeds were often crossed with the Eng- 

 lish breeds. To-day the first generation cross between the 

 Duroc-Jersey and the Poland-China, and between the 

 Poland-China and Chester White are popular animals 

 among the feeders. No attempt is made to breed from 

 them as it is well known that the later generations are 

 variable in color, size and conformation, and usually 

 possess less vigor than the animals of the original cross. 



First generation crosses between many of the stand- 

 ard breeds of beef cattle are raised, and frequently they 

 win the first prizes at the stock shows. The Shorthorn 

 and Aberdeen- Angus combination is popular. 



The Mediterranean breeds of poultry are sometimes 

 crossed with the heavier types. First crosses of Leg- 

 horns and Plymouth Rocks give birds which are not so apt 

 to become over-fat and yet are more valuable for meat 

 than the smaller Leghorns. 



The opportunities for improvement in this way 



