#Syncope or Fainting.#—­Syncope is the result of a suddenly produced anaemia of the brain from temporary weakening or arrest of the heart’s action.  In surgical practice, this condition is usually observed in nervous persons who have been subjected to pain, as in the reduction of a dislocation or the incision of a whitlow; or in those who have rapidly lost a considerable quantity of blood.  It may also follow the sudden withdrawal of fluid from a large cavity, as in tapping an abdomen for ascites, or withdrawing fluid from the pleural cavity.  Syncope sometimes occurs also during the administration of a general anaesthetic, especially if there is a tendency to sickness and the patient is not completely under.  During an operation the onset of syncope is often recognised by the cessation of oozing from the divided vessels before the general symptoms become manifest.

Clinical Features.—­When a person is about to faint he feels giddy, has surging sounds in his ears, and haziness of vision; he yawns, becomes pale and sick, and a free flow of saliva takes place into the mouth.  The pupils dilate; the pulse becomes small and almost imperceptible; the respirations shallow and hurried; consciousness gradually fades away, and he falls in a heap on the floor.

Sometimes vomiting ensues before the patient completely loses consciousness, and the muscular exertion entailed may ward off the actual faint.  This is frequently seen in threatened syncopal attacks during chloroform administration.

Recovery begins in a few seconds, the patient sighing or gasping, or, it may be, vomiting; the strength of the pulse gradually increases, and consciousness slowly returns.  In some cases, however, syncope is fatal.

Treatment.—­The head should at once be lowered—­in imitation of nature’s method—­to encourage the flow of blood to the brain, the patient, if necessary, being held up by the heels.  All tight clothing, especially round the neck or chest, must be loosened.  The heart may be stimulated reflexly by dashing cold water over the face or chest, or by rubbing the face vigorously with a rough towel.  The application of volatile substances, such as ammonia or smelling-salts, to the nose; the administration by the mouth of sal-volatile, whisky or brandy, and the intra-muscular injection of ether, are the most speedily efficacious remedies.  In severe cases the application of hot cloths over the heart, or of the faradic current over the line of the phrenic nerve, just above the clavicle, may be called for.

#Surgical Shock.#—­The condition known as surgical shock may be looked upon as a state of profound exhaustion of the mechanism that exists in the body for the transformation of energy.  This mechanism consists of (1) the brain, which, through certain special centres, regulates all vital activity; (2) the adrenal glands, the secretion of which—­adrenalin—­acting as a stimulant of the sympathetic system, so controls the tone of the blood vessels as to maintain efficient oxidation of the tissues; and (3) the liver, which stores and delivers glycogen as it is required by the muscles, and in addition, deals with the by-products of metabolism.