310 
R INSPIRATION. 
tion, and consequently with an invigorated nervous energy in all 
his muscles, a moderate gallop of half a mile would scarcely dis- 
turb his ordinary pulse or respirations. If he runs his two and 
a half or three miles in a race strongly contested, his respiration 
increases in number to two-thirds that of his pulse, with reflux 
of blood into the large veins : still the inspiration and expiration 
will be equal, with much less sighing and prolonged inspirations 
occurring ; and the ordinary breathing will the more quickly 
return on the horse resuming a tranquil state, as compared with 
the previous illustration. 
From the foregoing remarks, it will be observed, that the cha- 
racter of respiration in health is the equality of the two actions 
of the thorax, dilatation and contraction ; a reciprocal action of 
inspiration and expiration of uniform extent. Whenever this 
mutuality in the respiration is disturbed, disease exists in some 
part of the respiratory machine, and some impediment is operating, 
proceeding from a change of structure or function, or both. 
Inspiration may be quick or slow, short or prolonged, regular or 
interrupted, difficult or facile, thoracic or diaphragmatic, pain- 
ful, limited, or extensive. 
The movements in expiration may be hurried or prolonged, 
laborious and convulsive, or both these acts of breathing may be 
at the same time exceedingly limited or extensive; the whole 
having many modifications, and severally arising from particular 
causes and influences, thus constituting, in the performance of 
respiration, signs and characters of many diseases of the utmost 
importance in veterinary pathology. It is an attempt to describe, 
unmixed with any other symptoms, these indications of disorder 
that I principally intend by this essay ; and in whatever degree 
I may fail to accomplish the task, I shall feel gratified if I suc- 
ceed in making the production in some measure useful to the 
reader. 
The character of respiration in disease . — I will commence with 
the nasal passages, the changes of structure occurring in them, 
either temporary or permanent, which obstruct the ingress and 
egress of air to the lungs, and thereby alter the character of re- 
spiration. First, in enumeration, we have a tumefied state of the 
Schneiderian membrane from inflammatory action in catarrh, 
which in mild cases is not visible in the movements of the chest ; 
but, when the affection is severe, and inflammation runs high, 
with effusion into the mucous and submucous tissues, then the 
air to and from the lungs is impeded and sensibly felt. Occa- 
sionally the turbinata are enlarged, commonly on one side, possi- 
bly on both, advancing into the nasal fossa. Fractures of the 
face, and accumulations of pus in the maxillary sinus, also di- 
