OF VETERINARY MEDICINE. 29 



The stages of inflammation are three : 



1. Hot dry stage. 



2. Wet stage — the stage of efifusion. 



3. Stage of suppuration, or formation of 



pus. 



The hot, burning stage is characterized by hyperaemia, exuda- 

 tion of plastic substances, infiltration of the surrounding tissues, 

 discoloration of the tissues in the form of redness and suspension 

 of function. This stage is short, an average of six hours. 



In the wet stage, or stage of effusion, serum exudes from 

 the blood vessels. The serum is thin, non-coagulable (not plas- 

 tic) ; it infiltrates the surrounding tissues and produces oedema. 

 This second stage is long, indefinite, lasting from a day or two 

 to a month or more. It is called the wet stage from the effusion 

 of serum. It is particularly illustated in the inflammation of 

 mucous membranes. 



The formation of pus in the third stage is brought about by 

 the disorganization of tissue in which the inflammation occurs. 

 The eft'usion of serum, pressure upon the nerves, and altered 

 nutrition in a part result in a small focus of disorganized tis- 

 sue, which eventually grows into a cavity containing pus. 

 The pus-forming germs are most commonly the cocci (strepto- 

 and staphylo). These germs inoculated into healthy tissue will 

 produce suppuration, but is it possible to produce a suppurative 

 inflammation without them. Hamilton, the Scotch pathologist, 

 demonstrates this as follows : 



Sterilize the surface of a part, make an incision, and insert 

 a sterile capsule containing a drop of croton oil. Seal over the 

 wound with collodion and after three days you will find pus, 

 but no germs. As soon as the capsule is dissolved, the croton 

 oil cauterizes the part setting up an inflammation which runs 

 the various stages until pus is formed. 



Of the various terms used in describing inflammation, we 

 have the following: 



Induration — swelling hardens. 



Adhesion — a growing together of two surfaces; seen es- 

 pecially in pleurisy, where the costal pleura adheres to the pul- 

 monary pleura. 



