Phlebotomy, or VENESECTION, is, as applied to human beings, treated at BLEEDING, Vol. II. p. 221. The abstraction of blood was at one time considered the best and only remedy for the various diseases of horses and cattle, but at the present time it is comparatively rarely performed, except by veterinarians of the older school; but it is useful in subduing acute congestions, such as of the brain, in parturient apoplexy, congestion of the lungs, acute inflammation of the udder, and in a disease characterised by sudden swelling of the head and throat, called malignant œdema. The vessel selected for the operation is usually the superficial jugular vein, which in cattle is large and loosely situated under the skin of the neck.
In consequence of the mobility of the tissues surrounding the vein it cannot in cattle, as in horses, be raised and made sufficiently tense without the use of a cord tied round the animal's neck below the seat of the intended operation. This cord should be from to inch thick, pulled tight enough to arrest the flow of blood and cause the vein to become distended and tense. It should then be opened with the 'blood stick,' so as to pierce the skin and vein at one blow.
When a sufficient quantity of blood has been abstracted, say from 3 to 6 or even 8 quarts, the cord is slowly slackened so as to prevent a vacuum and the ingress of air into the vein, the lips of the wound brought into opposition and maintained there by a pin passed through them, and around it twine or tow is twisted in the form of a figure of 8. The pin should not be removed for at least thirty hours.