DISEASES OF THE RESPIRATORY ORGANS. 215 
moist stage being established. An examination of the pulse 
will assist the practitioner to a correct opinion; in number 
it will vary from sixty to one hundred, but in character it is 
uniformly somewhat full and soft in the early stage of the 
disease, only becoming quicker and feeble as debility ad¬ 
vances. 
Presuming the disease to pass through its stages without 
implicating any other structure besides the mucous mem¬ 
brane, there will be but little variation in the symptoms; after 
a few days the breathing becomes more tranquil, the pulse 
less frequent, the cough more sonorous, and the general 
appearance more cheerful; but in the majority of acute 
cases, particularly in young and plethoric animals, the dis¬ 
turbance extends to the parenchyma, deposits take place in 
the air vesicles, obliterating their cavities; purulent forma¬ 
tions occur in various parts commonly connected with dis¬ 
tended bronchiae, the pleural membrane ultimately becomes 
implicated, and fluid exudation takes place into the cavity 
of the thorax. 
All these complications may be distinguished with tolera¬ 
ble accuracy by auscultation. 
Obliteration of the air vesicles by deposits will be indi¬ 
cated by a loss of the murmur over a large portion of the lung, 
the sound only being distinct in the anterior and upper part 
of the thorax; large deposits of exudation matter, leading to 
a state of hepatization are frequent, and invariably give 
rise to the sibilous sound, which in its turn gives place to 
the cavernous rale as the deposits are softened in the centre, 
and cavities are formed containing pus or curdy matter 
similar to that found in scrofulous abscess in the human 
subject. 
Effusion is of all morbid conditions most easily distin¬ 
guished, unless peculiar complications should exist to mo¬ 
dify the signs. A well-defined grave sound at the supe¬ 
rior part of the chest, and the sudden cessation of it at a 
particular line, all below being obscured, is indicative of no 
other condition. Various degrees of sound will be noticed 
in many diseased states of the lung, but the sudden inter¬ 
ruption of the full sonorous murmur, and the substitution 
of nearly absolute silence below a certain point, may be safely 
taken as a sign of hydrothorax. 
Certain conditions may however exist, in which this very 
characteristic symptom is wanting, when effusion has ad¬ 
vanced even to a considerable extent; for instance, when 
the lungs are adherent to the sides of the che3t, the sound 
at the lower part is apparent; when consolidation of the 
