OF FARRIERY. 



]07 



CHAPTER VIII. 



OF ULCERS IN GENERAL; ON POLE- EVIL; FISTULOUS WITHERS; 

 ULCERS IN THE MOUTH; STRANGLES ; AND VIVES. 



OF ULCERS IN GENERAL. 



Ulceration is the process, by which sores, or 

 ulcers are produced in animal bodies. In this 

 operation the lymphatics appear to be at least 

 as active as the blood-vessels. An ulcer is a 

 chasm formed on the surface of the body by 

 removal of parts back into the system, by the 

 action of the absorbents. At first, it may be 

 difficult to conceive how a part of the body 

 can be removed by itself; but there is not 

 more difficulty in conceiving; this, than how a 

 body can form itself Both facts are equally 

 well confirmed. When it becomes necessary 

 that some whole living part should be re- 

 moved, it is evident that nature, in order to 

 effect this object, must not only confer a new 

 activity on the absorbents, but must throw the 

 part to be absorbed into a state which yields 

 to this operation. The absorption of whole 

 parts in disease, arises from several causes, 

 but those we have principally to contend with, 

 either arise from the parts becoming bruised, 

 or from constitutional irritability. 



Ulceration, or in other words, absorption, 

 takes place much more readily in the cellular 

 and adipose substance, than in muscles, ten- 

 dons, nerves, and blood vessels. Hence, in the 

 progress of pus to the surface of the body, ul- 



ceration often takes a circuitous course, for 

 the purpose of bringing the matter to the skin. 

 The skin itself being highly organized, con- 

 siderably retards the bursting of abscesses. 

 It is on this same account, that when ulcera- 

 tion is spreading, the edges of the skin hang 

 over the ulcerated part. 



When ulceration takes place, in conse- 

 quence of the death of an external part, it 

 occurs first on the outer edge, between the 

 dead and living substance. 



Abscesses constantly make their way to 

 the surface of the body by ulceration ; but as 

 Jsome textures more readily admit of being 

 absorbed than others, the matter often follows 

 a circuitous course before it can arrive at the 

 skin, hence showing the cause at once why 

 sinuses becomes formed. 



The parts which are situated between an 

 abscess, or any extraneous substance, and the 

 nearest surface, are those which are most sus- 

 ceptible of ulceration. This is one of the 

 most curious phenomenon connected with the 

 process under consideration. It shows that 

 there is a principle in the system, by which 

 parts are always prone to free themselves of 

 disease. Slight pressure from without will 

 even produce a thickening of parts, such aa 

 pi-essure from the saddle, the harne»», &c. ; 



