ON MAN AND ANIMALS. 
611 
losed. The synovia so necessary to preserve their flexibility 
becomes diminished and dried up. A certain inter-articular cre- 
pitation is heard indicative of such dryness. The step of such 
animal is infirm, and he is but too often found stumbling. Broken 
knees, lamenesses, abnormities of every kind, follow in quick suc- 
cession, appearing exteriorly in the form of windgalls, curbs, 
exostoses, spavins, & c. 
4. To augment the number of inspirations by hurrying the 
natural breathing. The inspirations which, in a state of repose in 
a horse in health, are from 10 to 12 per minute, become increased 
to 20 or 30, and during exertion even to the maximum of accele- 
ration as far as 130 per minute. The pulmonary tissue from un- 
natural dilatation becomes over-stretched and bursts. Rents of its 
texture follow, and the air escapes into the parenchymatous sub- 
stance, and thence underneath the pleura. To this we may chiefly 
attribute the cause of pulmonary emphysema, causing broken- 
wind, and rendering the animal incapable of work. 
5. At the same time it augments the pulsation, raising it from 
38 or 40 to 70 or 80, and possibly as high as 140 per minute. 
From that time the heart takes on gradually proportionate dila- 
tation, while the lungs and large bloodvessels suffer from too sud- 
den affluxes of blood, which, in consequence, is thrown back 
upon the brain, occasioning congestion. Depots of blood become 
established, the decomposition of which hastens the death of the 
animal, of which every day furnishes us with examples in the 
dead horses which are brought to our slaughter-houses. We have 
even seen race-horses fall dead ; the state of sur-excitation to 
which they had been pushed by the striving of their riders, elated 
at the idea of winning, having given rise to rupture of one of the 
principal bloodvessels. 
In regard to the pernicious effects of excessive labour, we may 
observe, what does the mischief in particular is the extreme speed 
at the time that the animal is over-weighted. This is the reason 
why our cavalry horses wear out quicker than those employed in 
the artillery service, though the latter work would seem the more 
exhausting. For a like reason, we see hunters and post-horses wear- 
ing less time than such as are worked more hours, but at a dimi- 
nished pace. Agricultural horses that work from six to eleven 
o’clock in the morning, and from two to six in the afternoon, and 
sometimes even more than that, last twice or thrice the time of others. 
The use we make of horses being twofold,' viz. for speed and 
for burthen, it is of importance that we should examine upon what 
in particular the two capabilities depend, which, found united in 
the same horse, constitute the reason why we give him the prefer- 
ence over others. It likewise behoves us to determine the exact 
