22 INFLAMMATION. 



•which thus become highly sensitive during inflammation the 

 feeling of pain must be due to the increase of germinal matter 

 of the nerves, as well as that of other tissues. Muscular 

 and other softer structures, though endowed with much sensi- 

 tiveness during health, are not nearly so painful in inflamma- 

 tion. This arises from their yielding nature, giving way and 

 allowing free swelling of the part, which in most cases seems 

 to relieve pain. The veterinarian has a good example of this 

 in lymphangitis, the pain and lameness of which seem to sub- 

 side as the swelling of the parts appears. In the treatment 

 this should be borne in mind, as remedies that promote swell- 

 ing (fomentations) afford very marked relief. 



Sivelling. — The swelling of inflammation depends upon — 1st 

 The congestion of the vessels ; and 2d. The exudation of liquor 

 sanguinis and the diapedesis of corpuscles into the tissues. 



Swelling of an external inflamed part may be looked upon — 

 except in the case of the articulations, where it is, when very 

 great, indicative of ulceration — as a favourable sign, its occur- 

 rence often afl'ording relief But when it occurs in the organs 

 essential to life, such as the parenchyma of the lungs, or upon 

 the glottis, its presence may soon put an end to the life of the 

 animal. Swelling is not always an indication of inflammatory 

 action ; the swellings of dropsy, anasarca, and of purpura and 

 scarlatina, are very different from those of inflammation. The 

 swelling of purpura is very characteristic, terminating abruptly, 

 superiorly, as if a cord had been drawn around the limb; 

 the swelling of anasarca will be found to be most bulky at 

 its most depending part. Tumours are also examples of swell- 

 ing without inflammation ; cartilage, which is non- vascular, 

 swells by its cells taking up more matter, and assuming the 

 form of large round corpuscles. In proportion as they take 

 up this matter, they enlarge in all directions, often forming 

 spots or protuberances on the surface of the articulation, as may 

 be seen in navicular lameness. 



Heat. — The temperature of tlie inflamed part seems to be con- 

 siderably increased, affecting the sensations of the observer as 

 weU as of the sufferer ; hence the name " inflammatio," a burn- 

 ing. But this increase of heat is not so decided as one would 

 imagine, and the experiments of Hunter go to prove that the 

 difference, in most cases, is not more than one degree : and. 



