PNEUMONIA. 105 



*' rotten as a pear/^ The obstructed circulation through 

 the lungs will account for the disorder we find manifesting 

 itself in the brain, particularly in the last stages of conges- 

 tive pneumonia. 



Hepatization is the term we apply to the change the 

 lungs undergo in consequence of inflammation, rendering 

 their substance, when cut into, liver-like or hepatic : instead 

 of presenting a pale pink, spongy, light, and elastic interior, 

 we find them reddened, solidified, and become heavy and con- 

 sistent; and, instead of floating in water, we find they sink. 



M. Rigot has well portrayed this change. " The hepa- 

 tized lung appears to have, and on occasions really has, 

 acquired increase of volume : its tissue is close ; it crepitates 

 no longer on pressure; on being cut, it does not present 

 one uniform redness, but is irregularly shaded with rose, 

 brown, and white tints, and at times with violet : these dif- 

 ferent colours, which give it a marbled aspect, are owing to 

 portions of parenchyma remaining sound, mingled with 

 blood, as well as to altered layers of cellular tissue. Cells 

 are also to be perceived within the parenchyma occupied 

 by the lobules of the lungs, which themselves appear 

 converted into homogeneous amaranthine -coloured sub- 

 stances. Here and there, divided bronchial tubes, and large 

 branches of veins and arteries, appear.^^ — '^The impermea- 

 bility of the lung prevents us from hearing the respiratory 

 murmur, by causing a dulness of sound on percussion oppo- 

 site the decased parts, and this may happen at one single 

 spot or in many places. A humid crepitous rale is heard 

 around these places when they are in a state of inflamma- 

 tion. The respiratory murmur becomes louder in the sound 

 parts than it was before; or in one entire lung, should the 

 other be attacked by inflammation. The respiration be- 

 comes irregular and catching ; the pulse tense, small, and 

 wiry; the cough dry, though sometimes humid; the skin 

 harsh. The horse does not lie down, or but for a short 

 time, and upon the aff'ected side." 



Should the symptoms continue beyond the sixth or 

 seventh day without any decided change, either for better or 



