POLL EVIL. 153 



without those strong remedies we have re- 

 commended in that disease*. 



* Since writing the above, I have discovered that the inflam- 

 raation which produces poll evil does not begin, as is usually the 

 case in other parts, on the surface, or in the cellular membrane 

 under the skin, but between tlie ligament of the neck and the 

 bones. When we consider the weight and position of the horse's 

 head, with the great length of the neck, it will readily appear 

 that the muscles alone are not capable of supporting and moving 

 so great a weight, under such mechanical disadvantages. Nature 

 has therefore provided a strong ligament, which is firmlj- fixed to 

 the back part of the head, whence it passes down over the 

 bones of the neck. It is not attciched to tlie first bone, but is 

 firmly fastened to the three next : it then passes over the three 

 other -bones of the neck in nearly a straight line to the withers, 

 where it is securely fixed, giving off a thin shp of ligament in its 

 passage, which is united to the last three bones. It is continued 

 iiom the withers to the back. This ligament, being elastic, 

 allows of sufficiei't motion in the neck, and so effectually assists 

 the muscles in supporting the head, that they never become 

 fatigued. 



Wlien a horse receives a violent blow on tliat part of the poll 

 whicl) covers the first bone of the neck, wiiich, as we have just 

 observed, is not attached to the ligament, the injury will be sus- 

 tained chiefly by the sensible parts placed between the bone and 

 the under surface of the ligament. The skin may also be liurl, 

 and a slight degree of superficial inflammation may take place. 

 But when infiammation has been thus produced between the 

 bone and the ligament, it is more likely to proceed to suppura- 

 tion, or to the formation of matter ; which being so deeply seated, 

 cannot find vent at the surface, by bursting the skin like a com- 

 mon abscess ; therefore it spreads under the ligament, and is so 

 i ong in arriving at the surface, that both the bones and iigamcnt. 



H 5 



