VETERINARY SCHOOL AT ALFORT. 
577 
work of which it is chiefly composed, cannot obliterate the large 
bronchial tubes, whose cartilaginous rings resist the peripheric 
pressure they have to support in the midst of this transformed 
pulmonary mass : the air, while permeating their canals, which 
remain open in the centre of the compact block of coagulated fibrine 
which now represents the lungs, conveys to an ear applied to the 
thoracic cavity a sound analogous to what it would produce in 
passing through the pipe of a whistle. It is this whistling sound or 
tubulans rale, perceptible at each respiration, which may be con- 
sidered as the most pathognomonic internal symptom of pneumonia. 
The grunt audible in the orifice of the nostrils modifies the tubulary 
rale at the moment of its production, and renders it more sonorous 
and shrill. It is an indication of the acuteness and severity of the 
malady. It increases with the disease, and disappears as the pa- 
tient recovers. The humid crepitating rale heard above the sound 
of the whistle, and in the vicinity of the effusion, is occasioned by 
the presence of the serosity, the product of inflammation in the 
small bronchial tubes still permeable to the air, the serosity finding 
its way through the vesicular parietes into the aerial canals. 
The supplementary murmur perceptible in the sound portions of 
the lungs is connected with the acceleration of the respiration, that 
multiplying the columns of air entering the lungs, and consequently 
increasing the sound produced by the collision of the fluid against 
the walls of the canals in which it circulates. 
5. The resolution of pneumonia is announced by the diminution 
and rapid disappearance of all the symptoms we have endeavoured 
to describe and explain. The period when the disease is most 
violent varies generally within the limits of the first, seventh, 
eighth, and ninth days. This latter is the extreme period, and if 
symptoms of resolution are not perceptible then, there will be but 
too much reason to apprehend that the disease will prove incurable. 
6. When pneumonia continues with unabated violence, and 
proceeds uninterruptedly towards an unfavourable termination, the 
persistence and aggravation of the symptoms announce the con- 
tinuance and consequent aggravation of the disease. Some of the 
symptoms will, however, become modified by the mere duration of 
the disease ; these are, for example, such as are dependent on the 
circulation. The mucous membranes become discoloured, and the 
pulse feeble in proportion as the disease increases ; the temperature 
of the skin, and that of the expired air, decreases in like measure; the 
respiratory sounds vary according to the mode and degree in which 
the pulmonary tissue becomes altered, and the general expression 
of the disease remains the same as at the period of its utmost 
severity, even though it is rapidly progressing towards an unfortu- 
nate issue. 
