ON DISEASES OF THE LUNGS IN HORSES. 
215 
development of tubercles or other accidental productions ; 4thly, of displace¬ 
ment and compression of the lungs by fluid effused into the chest. The loss 
of sound may be partial or general: it will return on the air-cells becoming 
permeable again. 
Augmentation of Murmur will accrue from accelerated respiration after 
exercise. Should this happen during rest, it is likely to result from dilata¬ 
tion of the heart or large vessels; in which case the sound is loud, and is 
heard throughout the lungs. Should the sound he louder in one lung alone, 
or in places only of both lungs, it is owing to a morbid state of lungs ; it being 
in the latter case in general referrible to non-permeability of certain parts of 
the organ. In such a case as this, it is probable that the healthy portions of 
lung in some measure compensate for the diseased parts, in admitting a larger 
quantity of air. For example, should the left lung become hepatized, the 
murmur in the right will become augmented; the same as partial hepatiza¬ 
tions will cause an increase in the surrounding healthy parts of the same lobe. 
In all cases, this augmented sound takes the name of supplementary respira¬ 
tion. Again, the breathing becomes supplementary, and to a remarkable de¬ 
gree, along the superior regions of the ribs, in pleurisy affecting either both 
sides or one only, followed by effusion, at the time that the lung, still perme¬ 
able, becomes pressed by the fluid into the upper parts of the chest. 
R ales or Rattles is the name given by Laennec to such unnatural sounds 
as may attend the entry or exit of air within the air-passages. This term, 
which has been restricted in its signification to the noise heard in the wind¬ 
pipe just before death, must here be considered to apph* in a general way to 
every anormal respiratory sound. In respect to the places whence proceed 
these pathological pectoral sounds, they have been classed as follows :— 
Bronchial Sounds 
Pulmonary Sounds 
Pleural Sounds 
{ 
{ 
1 
Humid or Mucous Rale 
Dry Rale 
Bronchial Respiration. 
Crepitous Rale, humid or di’y 
Sibilous Rale 
Cavernous Respiration. 
Guggling or gurgling Sound 
Rumbling or grumbling Sound. 
The Mucous Rale issues principally from the bronchial tubes. It may 
be compared in sound to the bursting of bubbles of air caused by blowing 
through a pipe into soapy water. It is occasioned by the presence of mucus 
or other fluid. Its existence will be temporary or permanent, according as 
the mucus or fluids continue or not within the tubes: sometimes it becomes 
converted into the sibilous rale. Cough excited by compression of the throat, 
by occasioning the expectoration or displacement of the mucus, sometimes 
extinguishes these sounds; at other times it creates them. Frequently an 
aecumulation of mucus within one large or several small divisions of the 
bronchia will cause suspension of the respiratory murmur in the interior of the 
lung, leading one to believe the lung is hepatized; one only need trot the 
horse, however, to dissipate any doubts of this kind. According as the air 
meets with resistance from the density of the secretions will the bubbles 
thereby created be large or small. Large bubbles ordinarily occasion a noise 
like the crackling of a purnp-suckcr falling after it has been raised. The 
same sound often accompanies the sibilous rale. It is observable in catarrhal 
bronchitis, when plastic mucositics abound. 'Phis sound is heard most dis¬ 
tinctly hehind the shoulder, opposite the large divisions of the bronchia: at 
times it is audible even at the termination of the windpipe. 
'I'liE Mucous Rale with large Buijhles becomes perceptible in simple 
