RESPIRATION. 
309 
the number of pulsations is increased during inspiration, the 
lungs shew signs of engorgement; the spleen is liable to disten- 
tion, and afflux of blood into the portal system may take place* 
This is of great importance to the knowledge of men on the 
“ turf/’ as jockeys, and will be the more obvious on a view of the 
action of the glottis during respiration. During great efforts of 
the animal the glottis is closed, and respiration suspended for 
the short period of considerable exertion. Sporting men well know 
that a horse can make but one great struggle in a race : to use 
their own diction, “ loose his head, and you finish and this is 
owing to the continuance of the heart’s action during a closed 
state of the glottis, and consequent engorgement of the lungs. 
But this state of the chest can be endured only for a very short 
period : the glottis is opened, the atmospheric air rushes through 
the trachea to the lungs, and the whole of the respiratory muscles 
are seen actively engaged in restoring the consensus between the 
respiration and the circulation, which is soon accomplished, pro- 
vided the animal is in vigorous health and good wind. If a 
horse labours under any of the impediments to respiration, more 
especially fat accumulated in idleness, or too little work for the 
food he has been indulged with, it will be found that the respi- 
rations increase more than the pulse during strong exercise, be- 
coming, instead of one to four, only one to two, or two to three. 
Take a horse that is ridden moderately as a hack, and lives on 
good food, and a liberal allowance of it, the interstices of his 
muscles filled up, and his neck full and firm in the subflavum, and 
presume that he has had a moderate allowance of water, and been 
at exercise for an hour, and discharged the faecal contents of the 
rectum — let him trot smartly or hand canter over a fallow or soft 
turf field for fifteen minutes, and his respirations will have in- 
creased to 35 or 40, and his pulse to 70 or 80 ; but the respiration 
will continue equal, accompanied with frequent sighs, or long- 
inspirations, arising, as before stated, from an increased action in 
the venous circulation, and a consequent augmentation of blood 
in the cavse and large veins entering the chest. The sounds of 
the heart are altered, and reflux of blood is observed in the jugu- 
lars to be much more than during slow or walking exercise : 
however, this tumult and commotion of the chest will gradually 
subside to its ordinary repose if the horse is allowed to remain 
quiet for a short time, and the inconvenience that has been given 
to the animal by the exertion will be so trifling as to leave no 
visible signs of its existence. On the other hand, let us suppose 
a thorough-bred horse brought to the post, having gone through 
his usual training, and a degree of work equal to the removal 
from his system of every particle of impeding material to respira- 
VOL. xiv. s s 
