A STUDY OF DISEASE IN GENERAL. 145 



which affect the digestive organs are more numerous and fre- 

 quent than all others to which sheep are liable. By their ex- 

 posure to the vicissitudes of the weather, although greatly pro- 

 tected by their woolly covering, also from being grazed on cold 

 and wet soil, unsuitable to their natural habits, diseases are fre- 

 quently induced, especially those of the feet, such as foot-rot. 

 The herding together in flocks facilitates the spread of infectious 

 ■diseases through the herd, and the attacks of flies and other 

 vermin during the summer months are a source of annoyance 

 and care to the sheep owner. Parasites are the most serious and 

 fatal causes of sheep diseases, producing a large proportion of 

 the losses. They affect the animal internally and externally, 

 causing debility and wasting, but at the same time they are 

 easily recognized, and yield readily to properly applied agents. 

 Diseases which affect limited areas or districts, due to some local 

 cause, are called enzootic. Sheep from their conditions of life 

 and management are frequently subject to enzootic diseases, a 

 number of a flock being affected simultaneously, causing the 

 necessary treatment to be applied in a wholesale or general man- 

 ner. In the treatment of large numbers of a flock it would be 

 impraticable to catch each individual member and dose it separ- 

 ately. To overcome this difficulty it is necessary to supply such 

 agents in the food, which, being consumed by the flock, will do 

 the most good, and for this reason such medicines as sulphate of 

 iron and salt are given in the feeding troughs; for foot-rot foot 

 baths (consisting of shallow troughs containing the desired 

 medicinal agents) through which the sheep are driven; dipping 

 or washing with agents to destroy parasites and salves of different 

 kinds have been found useful, the healthy as veil as the diseased 

 being submitted to the treatment. In the treatment of plethoric 

 diseases, such as apoplexy, phrenitis, and some congestive disor- 

 ders and blood derangements, bleeding is useful and frequently 

 resorted to. Purgatives are specially valuable on account of 



