8 VETERINARY LECTURES 



follows. The heat is not, however, so great as is thought, for the 

 temperature does not increase more than 2° or 3 ; and yet in an 

 inflamed foot there is a perceptible increase of heat. We can, 

 however, have heat without inflammation, as the body often becomes 

 heated from exercise or hard work. 



19. Pain is owing to the irritation of nerve fibres, from the 

 pressure caused by the distension of the effused blood materials. 

 Pain, however, varies in different portions of the body : it may be 

 reflex and far distant from the affected part ; in some places it 

 is dull, as when the mucous membranes are inflamed ; but when 

 fibro-serous or serous membranes are affected, as in rheumatism and 

 pleurisy, the pain is most acute and at times throbbing. Bone in 

 health is almost non-sensitive, but when under inflammation, from 

 its unyielding nature, the pain is excruciating. But we can have 

 pain without inflammation ; for instance, as in cramp or spasm. 



20. Redness is due to the accumulation of blood, coupled with 

 a distension of the vessels and a crowding of red corpuscles in the 

 part, and, finally, extravasation into the structures. Yet we can 

 have redness without inflammation. 



ai. Swelling arises from many causes, but in inflammation it is 

 occasioned by the congestion and exudation of the serous or watery 

 portions of the blood, and extravasation of the blood itself, owing to 

 the coats of the distended vessels giving way. Still, we have swell- 

 ing in various parts of the body without inflammation — as in dropsy, 

 from debility ; swelling of the legs, from plugging of bloodvessels or 

 want of tone in the tissues ; or the swellings of blains or ' howkes ' 

 (nettle-rash) in cattle. 



22. Yet, when all these signs are found combined — i.e., heat, 

 pain, redness, and swelling — they are characteristic of inflammation, 

 and cause more or less constitutional disturbance in the body, with 

 a certain amount of fever, according to the situation and nature of 

 the attack. 



23. Inflammation is of various kinds, such as acute (sharp and 

 quick), sub-acute (not quite so active), and chronic (of a slow 



