circuljVR disturbances. 121 



pressure, and if incised, a watery, pale straw colored fluid es- 

 capes. 



Microscopic. — The intercellular spaces are increased in ex- 

 tent, hence the cells are farther apart than normal and may be 

 undergoing degeneration or atrophy, or be swollen and con- 

 tain vacuoles. 



Effects. — The efiects of oedema \arv acc(jrding to the causa- 

 tive agent, the tissue invohed, and the length of duration of 

 the process. If the etiologic factor is capable of reproducing 

 or increasing in cpiantity, as infectious agents (liacillus of 

 Alalignant Oedema), there is more extensive tissue destruction 

 than when the oedema is prdduced by other agents. Oedema 

 of the meninges of the brain or spinal cord niav result in 

 degeneration and destructirm of the ncr^'e cells and death nf 

 the diseased animal. On the other hand oedema of the sub- 

 cutaneous tissues of the mctacarjial or metatarsal region is of 

 little consequence. Oedema of brief duration docs not, as a 

 rule, produce permanent injurv to the involved tissue, but an 

 oedema of long standing is of serious consequence liecam^e of 

 the extensive In'dropic infiltrations of the cells of the affected 

 tissue and because of the constant depletion of the system. 

 Hvdropic degeneration, thrombosis and necrosis are frerpicnt 

 sequellae of oedema. 



