150 PRACTICE OF EQUINE MEDICINE. 



are heard only on inspiration; best heard at the end of inspiration; 

 these are fine, crackling sounds, like salt thrown on a fire, or like 

 the sound caused by rolling hair between one's fingers. 



They are dry rales, and said to be pathognomonic of pneumonia. 

 They are usually present from twenty-four to forty-eight hours, 

 and then pass away. 



In the second stage, or stage of red hepatization, on inspection, 

 there is a loss of the expansive powers of the chest on affected side; 

 the respirations are panting in character; on percussion, there is 

 dulness on an uneven line over the affected portion; on ausculta- 

 tion, in the majority of cases, there is an absence of all respiratory 

 sounds (absence of the vesicular murmur) over the affected part, 

 while bronchial breathing may be heard above. 



In the third stage, as resolution commences, on auscultation, 

 there may be the returning rale, or rale redux crepitus; these moist 

 rales of all sizes are heard on inspiration and expiration. On per- 

 cussion, the dulness will be found to be getting less marked. 



How is the diagnosis made ? 



By the elevation of the temperature, 104° to 106° F.; by the 

 expectoration, which is often brownish in color (prune-juice ex- 

 pectoration); by the crepitant rales heard in the first stage; by the 

 dulness on percussion over the affected part (generally unilateral), 

 and the loss of all respiratory sounds over the affected part in the 

 6econd stage. 



What other diseases may be mistaken for acute lobar 

 pneumonia ? 



Acute bronchitis and pleurisy, principally. 



Give the differential diagnosis between acute bronchitis 

 and acute lobar pneumonia. 



Bronchitis is a bilateral disease, whereas pneumonia is generally 

 unilateral; in bronchitis the cough is accompanied with a whitish 

 expectoration, while in pneumonia it is of a brownish color, as a rule. 



In the first stage, on auscultation, in bronchitis, sibilant and 

 sonorous rales are heard on both sides of the chest, while in pneu- 

 monia crepitant rales are heard on one side only in the majority 

 of cases. 



In the second stage, percussion in bronchitis yields resonance 

 (both sides); in pneumonia, dulness over the affected part (one side, 



