CONCUSSION, in medicine, a sudden impression or shock communicated to the brain or to the whole nervous system, as the result of a severe injury, or collision of the body with some external object. as in a fall, or in the crash of a railway accident. It is usual to distinguish C. from the more mechanical results of injury, by observing its effect upon the circulation and on the general sensibility; and there can be no doubt that the distinction is well-founded, for in the first place death may follow from C. alone, without any appreciable destruction of texture; and 2d]y, C. may be followed by recovery within a few hours, leaving the local injury entirely unattended by consti tutional disturbance; or recovery may be complete, there having been no local injury at all. Under the immediate shock of injury, the patient is usually unconscious and insen sible, pale, cold, sometimes shivering, pulseless, or nearly so, the pupils inclining to contraction rather than dilatation, or in some cases natural; the breathing is irregular, slow, feeble, and sighing; the secretions are suspended; the stomach often yields up its contents; and the bowels and bladder may also be evacuated. This state ends either in death, or in gradual reaction, which may pass over into a state of inflammatory fever, with violently excited circulation, and greatly increased heat of the surface. In
the treatment of C., it is sometimes necessary to have recourse to stimulants; but in general, moderate heat applied to the surface, abundant supplies of fresh air, and careful adjustment of the injured parts, are all that is necessary till consciousness is somewhat restored, and the power of swallowing regained; some warm soup should then be given, with a small allowance of wine or other stimulant, proportioned to the age and habits of the individual; and the effect being carefully watched, this treatment may be continued until restoration is complete. If there be danger of failure of the breathing or heart's action, artificial respiration (see RESPIRATION) should be employed without delay; and the patient should be transferred as soon a.s possible from the place of tie accident to a warm and comfortable bed, where the necessary restoratives may be more conveniently used. The connection of the nervous system with the heart, in cases of C., is a very curious subject in physiology, and has been the subject of minute investigations by Bichat, Legallois, Wilson Philip, Marshall Hall, and many others