502 
JACOB HELMER. 
we have a catarrhal exudate. The glands are enlarged, mu¬ 
cous membrane swollen and tubes constricted. 
Auscultation in the first stage finds the sonorous rale. It is 
heard on both sides, both on inspiration and expiration. The 
sound is best heard over the middle third between the sixth 
and twelfth rib. The sonorous sound is due to the dryness 
of the tubes in connection with their diminished calibre. In 
the second stage, when the exudate is thrown out, we get a 
mucus rale, both on inspiration and expiration. The sound 
comes and goes. The secretion may or may not be expecto¬ 
rated. We may not always hear the mucus rale. Percussion 
in the first stage usually gives an increased resonance. In fat 
horses it is almost impossible to distinguish. In the second 
stage the change in resonance in percussion is slight. 
In capillary bronchitis percussion }delds increased reson¬ 
ance on both sides, in both stages, unless in old animals. 
There is auscultation, a mucus rale and hissing sound. In 
the second stage we find sub-mucus rale. Old animals may 
not be able to cough up the mucus which may block some of 
the tubes. 
Asthma. —This morbid condition is a neurosis. It gives 
rise to paroxysms of dyspnoea at recurring intervals. It is 
probably due to constriction of the circular fibres of the 
bronchial tubes, which cause a wheezy breathing while the 
paroxysm continues. 
Pulmonary Emphysema. —This is a condition characterized 
by loss of elastic power in the air cells. The walls become 
stretched and contain more than a natural amount of air. 
There are two varieties: the vesicular and the interstitial. 
In the former, the excess of air in the air cells ; in the latter 
it is in the connective tissue between the cells. The tissues 
may become ruptures and the cells come together, thus form¬ 
ing large bladders. Inspection notes that the chest walls 'are 
enlarged. The abdominal muscles are brought into use in 
proportion as the disease has advanced. The expiratory 
movement is much prolonged, and consists of three parts. 
A movement, pause, then another movement. Percussion 
gives increased resonance over portions of the chest. Aus-' 
