WEST OF ENGLAND VETERINARY MEDICAL ASSOCIATION. 809 
and in raatcbing tbat of an healthy animal we can observe two distinct 
movements : 
1st. Inspiration caused by the contraction of the inspiratory muscles, 
2nd. Expiration brought about by two causes, viz. a mechanical force 
by the resiliency of the cartilaginous ends of the ribs, and ensuing on that 
a vital force by the contraction of the expiratory muscles. And I have 
yet to speak of a third and very essential motive expiratory power, which 
resides in the lung structure itself, and assists these two last named. I 
refer to the elastic fibres and non-striated muscular tissue which surround 
the thin cartilaginous plates of the smaller bronchial tubes; but, before 
proceeding, it may be as well to review for one moment the minute 
anatomy of these parts. 
When the bronchial tubes become very small they lose their complete 
cartilaginous rings, and are merely formed of thin, irregularly placed 
plates of cartilage, united by fibrous membrane, and surrounded by layers 
of non-striated muscular fibres. In their more intimate ramifications 
these cartilaginous plates disappear altogether, the fibrous membrane is 
continued on into the air-cells with longitudinal elastic fasciculi, taking 
the place of these muscular fibres, and running between this fibrous 
membrane and the lining mucous membrane into their cmcal extremities. 
Now, it is these layers of non-striated muscular tissue which become 
atrophied in conjunction with those of the stomach, and being, as they 
are, continuous, or may be the self-same thing, but in greater quantity, 
as the elastic fasciculi spoken of, the whole resilient or contractile power 
of the lung structure itself becomes either partially or wholly lost. 
Now to refer back to the two first-mentioned expiratory forces, viz. 
the resiliency of the ribs and the contraction of the expiratory muscles. 
In normal respiration the power of the one ensues so truly on the cessa¬ 
tion of that of the other that the observer cannot detect when the one 
ceases and the other commences ; but if we watch the broken-winded 
animal we can very readily detect these two distinct efforts; the vital 
action of the muscles appears to be tardy in taking up the resiliency of 
the ribs. We know full well that the elasticity of the cartilaginous ends 
of the ribs is not affected, and we are also aware that the expiratory 
muscles are as full of strength as ever ; then the only respiratory power 
which is lost must be that resident in the lung structure itself, and such' 
has already been demonstrated. 
This delicate and peculiar muscular tissue has become paralysed from 
sympathy with the other peripheries of its parent trunk, and con¬ 
sequently the expiratory muscles have a double duty to perform, which 
they, being supplied with a certain amount of electricity only, must 
accomplish by the consumption of a larger space of time. 
It is not that they do not immediately take up the resiliency of the 
ribs, but they complete their portion of the work much slower than do 
the ribs the first portion, and consequently the difference in the celerity 
of the two movements becomes very visible. A short, dry cough, in¬ 
creased when feeding on dry musty provender, by pressure from without 
on the peculiarly irritable larynx, or by exertion, is a chief concomitant 
symptom, the same being associated with flatulence. 
As a result of the paralysed condition of the pneumogastric peripheries 
which are distributed on the stomach, the muscular coat of that viscus 
becomes flaccid and loses its tonicity, the organ becomes larger in calibre, 
and, as a result, the process of digestion becomes impaired. The ingesta 
are not acted upon as in the normal state; and, as a sequence, elimination 
of gas occurs, causing the flatulence always observed. 
The cough, consequent on the irritable condition of the larynx, we 
