262 
MANUAL OF MODERN FARRIERY. 
as glanders, the veterinary art may keep a horse in a con¬ 
dition to be ridden or driven at considerable speed without 
knocking him up, but not so with diseased lungs. 
It is not to be wondered at, that so many horses are 
afflicted with lung complaints, most of them resulting from 
carelessness. The poor animals are too often over-heated, 
and afterwards put into cold stables in a state of profuse 
perspiration, and allowed to dry. This should never be the 
case. The animal ought to be instantly rubbed down, until 
his coat is quite dry. If this is not attended to, inflamma¬ 
tion of the lungs and a host of other complaints may be 
the consequence. 
THE HEART. 
The heart is enclosed within a membrane or bag, called 
the pericardium, plate ix. fig. 1, c, and both together occupy 
the middle space of the cavity of the chest. The pericar¬ 
dium contains within it and throws out a pale yellow serous 
fluid, which serves to lubricate the contiguous surfaces of 
the sac, and to preserve them against any ill consequences 
arising from friction. 
The use of the pericardium is to confine the heart in its 
situation, to sustain it in its reciprocal action with the 
lungs, and guarding it from any undue collision, and to 
serve as a guard to the heart. When the pericardium or 
the heart becomes inflamed, an undue secretion of this fluid 
is induced, sometimes to such an extent as to obstruct the 
beating of the heart. When such is the case, the animal 
is said to have dropsy of the heart. Its symptoms are very 
similar to inflammation of the lungs, and consequently it is 
difficult to detect which of the two maladies the animal 
labours under. 
The heart itself, fig. X, 5, is the organ by which the blood 
