Predisposing Causes of Roaring. 55 



majority of Italian and Spanish horses have this kind of 

 head, and yet they are nearly exempt from the noise in 

 respiration. And Charon has shown how little such a forma- 

 tion has to do with the defect in question; as among 297 

 horses which were Eoarers, only nineteen had this shape 

 of head to a marked degree, thirty-three had it but slightly, 

 and 245 had heads of the ordinary shape. 



Another supposed predisposing cause is narrowness be- 

 tween the branches of the lower jaw, which does not admit 

 of sufficient space for the larynx, and which is therefore 

 compressed. This supposition has also been prevalent in 

 France, but in reality it has no foundation ; as the space, 

 which is rather variable in dimensions, has been found as 

 wide in Roarers as in sound horses — demonstrating that 

 the conformation has no influence in the causation of 

 Roaring. It is to be observed, however, that horses with 

 their heads " badly set-on " and diminished space between 

 the branches of the lower jaw, will, when ridden or driven 

 with the nose pulled in or to one side, sometimes make a 

 noise in breathing, but this is different to that of Roaring. 



Moeller remarks that horses with a thick fleshy neck and 

 narrow lower jaw, are worse Roarers than those of the 

 opposite conformation. 



So far, then, as certain conformations are concerned, I 

 am of opinion that they have very little, if any, influence 

 on the production of Roaring, the existence of this defect 

 in an animal of a certain shape being, in my experience, a 

 mere coincidence. 



8. Management. 



There can be little doubt that the management, or rather 

 mismanagement, of horses often predisposes them to Roar- 

 ino-. The artificial conditions in which they are bred, reared, 

 and worked, necessitated by climate and the demands of 

 civilization, and also those measures resorted to for im- 

 proving them, certainly have a tendency to develop altered 



