8 J. E. WODSEDALEK. 



the mule has an excellent appetite. However, the mule can go 

 longer without food and can live on coarser and more unpalatable 

 food than could be expected to give results with the horse. 

 Contrary to a prevailing belief also, the mule is equally suscept- 

 ible to various diseases as the horse. In the Philippines our 

 mules suffered as much as horses from surra. Glanders has 

 always been dreaded as one of the scourges of the army mule. 

 Even colic and other digestive troubles familiar to horse raisers 

 also occur among mules." 



Plumb ('06) says: "The characteristics of the mule partake 

 of both sire and dam. There is the long ear, slender body, 

 tufted or slightly haired tail, and small, slender foot, and braying 

 voice of the ass." 



"The temperament of the mule is quiet and patient, while for 

 steadiness under the collar and hard pulling he has no equal in 

 the equine world. . . . Horses are more nervous and uncertain 

 in temperament than mules, and are more subject to fright and 

 consequent runaway. 



"The endurance of the mule is remarkable. . . . Mules usually 

 live to a greater age than horses, and perform their work with 

 regularity and on less feed, a most important point in their favor. 

 Cases are recorded of mules living to seventy years of age. . . . 

 The resistance of the mule to disease, its activity, sureness of foot, 

 docility, and easiness of keep, have resulted in its finding much 

 favor in the army service." The sureness of foot is no doubt 

 inherited from the ass. 



That mules and hinnies are sterile is a well-known fact. And 

 if degeneration of the sex cells of all of these hybrids is as pro- 

 nounced as it was found to be in the material studied in this in- 

 vestigation and in all probability it is the cause of sterility 

 will remain obvious. A few cases of fertile mules have been 

 recorded, but careful investigations show that such records are 

 not authentic and practically all of the writers on mules regard 

 them as unreliable. 



Lydekker ('12) says: "With the possible exception of a few 

 instances in which the female is stated to have produced off- 

 spring, the mule is sterile; as, indeed, might be expected to be 

 the case when the difference between its parents is borne in 

 mind." 



