64 INFLAMMATION. 



while in the surrounding parts, where the swelling is less 

 prominent, serous effusion is found mingled with the solid 

 deposition. In anasarcous or oedematous affections, the 

 effusion seems altogether of a fluid nature. 



CAUSES OF INFLAMMATION. 



Inflammation may arise in a great variety of ways, some 

 of which are obvious to us, while others are mysterious, or 

 concealed from our view. Numerous and various however 

 as these are, they admit of classification into accidental, 

 spontaneous, and sympathetic. An inflammation is said to 

 be accidental when its exciting cause is self-evident, or ex- 

 ternal to the body ; comprehending all such as arise from 

 mechanical and chemical injuries, as well as such as are 

 ascribable to atmospheric vicissitudes. Spontaneous inflam- 

 mations are imagined to spring up of their own accord ; or 

 without any apparent cause : they are mostly what are called 

 inward affections. Sympathetic inflammations owe their 

 production to disease in other parts. 



Mechanical Injuries comprise wounds, contusions, and 

 abrasions ; sprains, dislocations, and fractures ; and undue 

 exertion of any organ_, or of the body. 



Chemical Excitants comprise all such substances as 

 possess properties of an acrid or poisonous nature : they are 

 the mineral acids, the caustic alkalies, and the metallic 

 salts which we are in the habit of using in our practice of 

 medicine. 



States of the Atmosphere — heat or cold, moisture or 

 dryness, in their turn become excitants of inflammation ; 

 their mischievous agency residing more in the vicissitudes 

 than in any un healthiness in our climate from their excess. 

 They may operate either directly, as excitants ; or indi- 

 rectly, as predisposing causes. Horses turned out from 

 warm stables and exposed to the open air, even during the 

 inclement seasons of the year, seldom experience any direct 

 inflammation from the change ; though the reverse of this 

 vicissitude cannot be practised without danger, especially 



