These are remedies which, by a direct influence, depress the vital actions. I shall treat, under this general head, of the sedatives which may be considered as universal, and afterwards, in separate classes, of those which, though felt throughout the system, have a special direction to some particular part of it, as the arterial, nervous, cerebral, and spinal sedatives. The influences which may be regarded as strictly universal are cold, water, and depletion either direct or indirect.