156 MANUAL OF EQUINE MEDICINE. 



exudation of a large quantity of coagulable material into 

 the tissue. 



Acute inflammation of the lungs is termed croupous, from 

 its resemblance to the pathological changes resulting in 

 croup. 



It is also termed lobar, because it almost always invades a 

 large part of the lung. 



There are three stages in this inflammatory process, but 

 it must not be imagined that each one occurs simultaneously 

 throughout the whole of the aS"ected portion of the lung. 

 On the contrary, the changes proceed irregularly, and while 

 one portion is in the second stage another may be in the 

 third, thus accounting for the marbled appearance of con- 

 solidated lung (Green). 



The stages are firstly that of engorgement, secondly, that 

 of red hepatization, and thirdly, that of grey hepatization. 



In the first stage the lung becomes very vascular, and the 

 changes in the vessels and circulation are such as already 

 mentioned under 'Inflammation.' The absolute weight and 

 specific gravity of the lungs are increased, their elasticity is 

 diminished, and they are less crepitant and more friable 

 than normally. They are of a dark red colour, and pit 

 on pressure, and the cut surface yields a red, frothy, tena- 

 cious, viscid liquid. 



In the second stage, that of red hepatization, there is 

 exudation of liquor sanguinis and migration of blood-cells 

 into the pulmonary tissue. The exuded liquids coagulate 

 in the vesicles and terminal bronchioles, and the coagulum 

 contains many white and some red blood-cells. 



The lung is of a dark reddish hue, often passing into 

 grey. It is much heavier than in the first stage, and 

 is increased in size, so as to be often marked by the 

 ribs. 



It is quite solid, sinks in water, and cannot be artificially 



