AFFUSION.

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in some cases it has been employed for twenty minutes. After the affu-sion the body should be carefully wiped dry, the patient wrapped upwarm, and placed in bed.

Effects .—The effects of affusion depend partly on the temperature ofthe water, and partly also on the sudden and violent shock given to thesystem by the mechanical impulse of the water ; hence the reason whythe effects vary,- according to the height from which the liquid ispoured.

1. Of the affusion of cold watei —that is, of water whose temperature isbetween 32° F. and 60° F. To a certain extent the effect of this agentis analogous to that of the cold bath, but modified by two circumstances,namely, the short period during which the cold is applied, and the me-chanical influence of the stream: hence, its primary effects are verytransient, and re-action follows very speedily. By a long continuance ofaffusion, however, the heat of the body is very considerably reduced, andthe same diminution of vital action occurs as when the cold bath isemployed. The sensation of cold, the constriction of the skin, and thecontraction of the superficial vessels, first experienced in the part towhich the water is applied, is very speedily communicated to the rest ofthe system by sympathy, in consequence of the shock; the effects ofwhich are perceived in the nervous, vascular, secreting, and cutaneoussystems. The temperature of the whole body falls, the pulse becomesreduced in volume and frequency, the respiration is irregular, and con-vulsive shiverings take place, faintness, and, in fact, all the effects alreadydescribed of the cold bath are produced. During this condition theexcretions are suspended. “ When,” says Dr. Copland, “ the stream ofwater is considerable, and falls from some height upon the head, theeffect on the nervous system is often very remarkable, and approachesmore nearly than any other phenomenon with which I am acquainted toelectro-motive or galvanic agency.”

After the affusion, re-action is soon set up, the heat of the body is re-established, the pulse becomes full and regular, though sometimesreduced in frequency, the thirst is diminished, and frequently perspira-tion and tendency to sleep are observed.

Cold affusion is used principally in those cases where it is considereddesirable to make a powerful and sudden impression on the system: foras a mere cooling agent it is inferior to some other modes of applyingwater. Thus it is employed, for the most part, in fevers, and affectionsof the nervous system. It is objectionable in visceral inflammation, onaccount of the determination of blood which it produces to the internalparts. Cold affusion has been employed with great benefit in fevers,both continued and intermittent. It may be used with safety, accordingto Dr. Currie and others, “ when there is no sense of chilliness present,when the heat of the surface is steadily above what is natural, and whenthere is no general or profuse perspiration.” It is inadmissible duringeither the cold or the sweating stage of fever, as also in the hot stage,when the heat is not greater than ordinary. In some instances it seemsto act by the shock it communicates to the system; for the effect isalmost immediate, the disease being at once cut short. The patient hasfallen asleep immediately afterwards, profuse perspiration has succeeded,and from that time recovery begun to take place. This plan of extin-guishing a fever, however, frequently fails ; and in that event the patient