THE THORAX IN THE HORSE. 
683 
of disease of the pulmonary organs in the horse are detect- 
able with more or less facility. ] . Pulmonary catarrh, acute 
or chronic. 2. Infiltration into the tissue of the large lobes 
of the lungs. 3 . The formation of large caverns. 4. Effu- 
sion into the pleural sacs. Continuous researches through a 
series of years have especially demonstrated the impossibility 
of recognising oedemas and pulmonary emphysema. 
As has been observed before, the anterior part of the 
thorax, that included between the shoulders, is not suscep- 
tible of having physical signs elicited out of it, either by 
auscultation or percussion, anywise calculated to demon- 
strate the nature of pulmonary disease. This accounts for 
Muller directing his researches to no part save what is 
posterior to the shoulder. About the middle of which latter 
space it is that, in its normal condition, percussion yields a 
full and clear sound. Ascending towards the vertebral 
column, the sound becomes duller, on account of the great 
thickness of muscle at this part. And as we go downwards, 
it is the same with most animals on the left side, on account 
of the presence of the heart. As we approach the abdominal 
cavity, the sound grows rather duller and becomes changed 
into a tympanitic one, proper to that cavity. Percussion 
by means of the fingers is sufficient for practice. The 
stethoscope is of no use, save it be for auscultation of the 
sounds of the heart. M. Muller especially remarks that, 
with animals more than with man, percussion and auscultation, 
if we are not in the constant habit of practising it, often 
leads to great errors, which is the principal cause why such 
means are so much neglected. 
In the sound horse one scarcely hears any sound by the 
application of the ear against the thorax ; at the very most 
we are able to descry a very light murmur during deep 
inspirations. Distinct vesicular sound denotes then an anor- 
mal condition ; it is the sign of catarrh or of pnuemonia, 
commencing at the part auscultated, or else of a morbid infil- 
tration of another part of the lungs. After a slight movement 
we perceive the normal sound, a distinct murmur, is heard, 
and continues up to close to the shoulder-blades. 
Signs of Catarrh. — The sound elicited by percussion 
differs not ordinarily from the normal sound. But it may 
be clearer and fuller, though without being tympanitic. 
By auscultation, the respiratory sound is perceived to be 
stronger, as though the animal had been submitted to a brisk 
movement. Often wc have but a humid rale towards the 
large divisions of the bronchial tubes. This rale may offer 
of itself different qualities, and be more or less mucous : 
never is it clear under simple catarrh without exudation in 
