INSENSIBLE PERSPIRATION AND SWEAT

The excretory activity of the living human skin is a biologic phenomenon to which attention has long been given. The response to exertion and to atmospheric temperature in the form of visible perspiration is recognized as a device whereby the organism not only regulates temperature but also eliminates certain products of metabolism. That there is a constant similar loss of material through the skin without the visible collection of water on its surface was made clear long ago by Sanctorius, who in 1614 published the results of extensive experiments on the "insensible perspiration." It is of interest, in this connection, that Dr. John Lining, a versatile and careful experimenter, made further observations of this constant loss of body weight during his thirty years' practice of medicine in Charleston, S. C., before the Revolution. The so-called insensible perspiration comprises the material lost from the body in gaseous form; it is made