158 INFLAMMATION OF THE JUGULAR VEIN. 
but is very seldom seen. The disease scarcely ever occurs without a 
wound of the vessel, though it must be allowed that inflammatory 
processes may extend from without to the wall of the vein. Such a 
case has been described by Peters. 
Symptoms. On removing the pin a day or two after blood-letting, 
the skin wound, instead of being closed and dry, is swollen, and dis¬ 
charges a somewhat dark fluid blood. Within the next few days the 
swelling enlarges, and the vein is now found to consist of a round, firm 
fixed cord, which extends from the wound in the skin to a varying 
distance above and below. The latter symptom proves the existence 
of a thrombus. The discharge of blood may be produced by extrava¬ 
sation under the skin, and, therefore, it is important to examine the 
vein. Filling of the vein on pressure at the base of the neck and 
collapse on removal of the pressure prove the non-existence of a 
thrombus. The use of a probe for diagnosis is not only superfluous 
but dangerous, because clotting and embolism in the lungs may thus 
be produced. 
During the next few days the wound discharges decomposed blood, 
which is later mixed with clots and pus. The swelling increases 
towards the head, and more or less severe bleeding may take place, 
especially during feeding. If thombus formation is rapid, cerebral 
disturbance resembling staggers may be produced, because the blood is 
unable to escape freely from the brain. 
Endophlebitis septica rapidly involves the several venous coats and 
surrounding connective tissues, producing multiple abscesses. Septic 
decomposition of the thrombus may produce pyaemia, but this seldom 
occurs, for the blood usually coagulates quickly within the vessel, 
completely closing it before septic decomposition can set in, or emboli 
be carried to the heart or lungs. Embolic pneumonia is, however, 
occasionally produced, and is invariably fatal. Where this complication 
is averted the disease usually takes a chronic course. The thrombus 
undergoes purulent or septic degeneration, the thickening of the venous 
wall finally leads to complete occlusion; obturation or obliteration 
usually occurring in three to four weeks. Inflammatory processes, the 
repeated abscess formation, and circulatory disturbances gradually dis- 
appeai, ciiculation being re-established by dilatation of collateral vessels. 
Skin veins sometimes become as large as a man’s finger, thus completing 
the communication between the still patent portions of the vessel. 
Prognosis. So far as the animal’s life is concerned, the disease usually 
takes a favourable course, unless where pulmonary embolism supervenes, 
producing dyspnoea, high fever, &c. Although obliteration of the 
vessel produces no lasting bad results, the animal cannot be worked 
during the active stages of the disease, nor can a horse with obliterated 
