DISEASES OF HORSES AND CATTLE. 89 



disturb the breathing, and we find this the case in 

 heaves. I have made a number of post-mortem ex- 

 aminations and failed to find, either by the naked 

 eye or the microscope, anything wrong with the 

 lung, although the animal had been affected with 

 heaves for a number of years. There are horses 

 whose lungs have been affected with inflammation 

 and a part becomes consolidated which will heave 

 just as a heaving horse would do; but the great 

 majority of horses affected with heaves have no 

 apparent disease of the lungs, therefore the ma- 

 jority of the profession find and believe it to be 

 a deranged state of the digestive organs. Profes- 

 sor Robertson says: "It is generally admitted to 

 be true that to this abnormal condition is attached 

 a certain amount of disposition or capability of 

 propagation from parent to progeny. Not that 

 those who support this idea suppose that the exact 

 paralysis of lung-tissue is received as an inherit- 

 ance from parent, but rather that, born with a 

 certain bodily conformation or temperament, the 

 animals are, under the same conditions and sur- 

 roundings, more liable to become sufferers from 

 this particular disordered condition than others not 

 possessed of the same congenital constitutions." 

 Certain breeds of horses are more subject to heaves 

 than others. Coarse-bred, high-boned, pot-bellied 

 animals are more frequently affected with it than 

 the fine, round, well-built horse. The kind of food 

 the animal is fed on and also the quantity is a 

 cause of heaves. Musty, innutritious, bulky, dusty 

 food, with a full allowance of water and put to 



