INFLAMMATION. 57 



The looser the meshes, the more effusion and the less pain. If 

 -the structure is tough and resisting, the pain becomes intense. The 

 white cells stick to sides of the vessels, the red remaining in the 

 centre of the stream.* The white gradually go through the walla 

 of the vessels and get outside. 



Where the stasis is more marked the red cells do the same. 



What are the parenchymatous changes ? 



The cellular elements of the tissues undergo change in form 

 and nutrition. The chemical interchanges which constitute normal 

 nutrition, and which are carried on between the cells of the tissue 

 and the liqnid furnished to the cells by the blood, are modified in 

 character or extent, and the cells themselves are modified in form. 

 The white cells increase in size and divide, and the connective-tissue 

 cells do the same ; some form new cells, while others undergo fatty 

 degeneration. 



What is the aetiology of inflammation ? 



The causes may be traumatic, toxic, parasitic, infectious, con- 

 stitutional, trophic, metastatic. 



How does traumatism cause inflammation? 



Either mechanically, in shape of cuts, pressure, crushing, etc. ; 

 or physically — extreme heat or cold, electricity, modification of 

 temperature ; or chemically — acids, alkalies. 



What are the toxic causes ? 



These act indirectly from chemicals introduced from without, 

 as arsenic, phosphorus, etc.; or are formed in the body, as the 

 products of putrefactive changes. 



In what way do parasites cause inflammation ? 



The vegetable parasites are mostly fungi, and act locally on the 

 skin and mucous membranes, as favus, thrush. The animal parasites 

 act locally at their entrance, or in remote parts, from reproduc- 

 tion. 



The infectious causes are what? 



The diseases produced in this way are caused by bacilli special 

 to that particular disease, as the bacilli of tuberculosis, glanders, 

 •erysipelas, etc. 



