DISEASES OF HEART, BLOOD VESSELS, AND LYMPHATICS. 263 
CONGESTION OF THE HEART. 
Congestion, or an accumulation of the blood in the cavities of the 
heart, may occur in consequence of fibrinous deposits interfering 
with the free movements of the valves, usually the product of endo- 
carditis or as a result of excessive muscular exertion. ; 
Symptoms are great difficulty of breathing, paleness of the visible 
mucous membranes, great anxiety, frequently accompanied by a gen- 
eral tremor and cold perspiration, followed by death. It usually 
results in death very quickly. 
CYANOSIS OF NEWBORN FOALS. 
This is a condition sometimes found in foals immediately after 
birth, and is due to nonclosure of the foramen ovale, which allows a 
mixture of the venous with the arterial blood in the left cavities of 
the heart. It is characterized by a dark purple or bluish color of the 
visible mucous membranes, shortness of breath, and a general feeble- 
ness. Foals thus affected generally live only a few hours after birth. 
DISEASES OF ARTERIES, OR ARTERITIS AND ENDARTERITIS. 
Inflammation of arteries is rarely observed in the horse as a pri- 
mary affection. Direct injuries, such as blows, may produce a con- 
tusion and subsequent inflammation of the wall of an artery; severe 
muscular strain may involve an arterial trunk; hypertrophy of the 
heart, by increasing arterial tension, may result in the production of 
a general endarteritis. Septic infection may affect the inner coat 
and ultimately involve all three, or it may be the result of an inflam- 
mation in the vicinity of the vessels, etc. Inflammation of arteries, 
whatever the cause may be, often leads to very serious results in the 
development of secondary changes in their walls. Arteritis may be 
acute, subacute, or chronic; when the inner coat alone is affected it 
is known as endarteritis. 
Symptoms.—Arteritis is characterized by a painful swelling along 
the inflamed vessel, throbbing pulse, coldness of the parts supplied by 
the inflamed vessel, sometimes the formation of gangrenous sloughs, 
suppuration, abscess, etc. In an inflammation of the iliac arteries we 
find coldness and excessive lameness or paralysis of one or both hind 
limbs. 
Pathotogy.—In acute arteritis we find swelling along the vessel, 
loss of elasticity, friability, and thickening of the walls; a roughness 
and loss of gloss of the inner coat, with the formation of coagula or 
pus in the vessel. Subacute or chronic arteritis may affect only the 
outer coat (periarteritis), both the outer and middle coat, or the 
inner coat alone (endarteritis); and by weakening the respective 
coats leads to rupture, aneurism, or to degenerations, such as bony, 
calcareous, fatty, atheromatous, etc. It may also lead to sclerosis or 
