24 THEORY AND PRACTICE 



4. Pain — Dolor. 



5. Altered function of the affected organ. 



The swelling in active congestion is resilient — press the part 

 with the finger and the depression at once vanishes. 

 The topical signs of passive congestion are : 



1. Swelling of an oedematous nature, i. e., 



doughy, inelastic; swollen tissue pits 

 on pressure. 



2. Congested area is sharply circum- 



scribed. 



3. Passive congestion tends to degenera- 



tion, never to inflammation. 



In active congestion the swelling is resilient, it fades away 

 imperceptibly into the healthy part ; the congestion tends to run 

 into inflammation on account of altered nutrition ; the liquid 

 oozing through' the pores of the vessels is plastic and the swell- 

 ing is apt to become permanent; and it may produce death by 

 gangrene. 



In passive congestion the swelling is doughy, and is sharply 

 circumscribed ; the congestion tends to degeneration, never in- 

 flammation ; the liquid oozing through the pores of the veins is 

 not inclined to coagulate nor organize. 



In passive congestion of the lungs an apparently paradoxical 

 condition occurs because the blood leading tO' the lungs is venous, 

 although carried by arteries ; and that going away is arterial, 

 but carried by veins. We call it passive congestion of the 

 lungs when due to defective cardiac power, and active when due 

 to diminished arterial resistence. 



RESULTS OF ACTIVE CONGESTION. 



When active congestion occurs in a part of considerable size 

 and that in excess, moist gangrene results. Gangrene is of two 

 kinds, moist and dry. Moist gangrene occurs in tissues whose 

 nutrition has been suddenly cut off and which therefore dies. 

 The dead part is moist gangrene. Dry gangrene is the result of 

 starvation, that is, when the nutrition to a part is slowly cut off. 



In moist gangrene the part is cold, insensible, and if punc- 



