To the Editor:
—Three years ago, at the meeting of the Pennsylvania Railroad Surgeons' Association, I read a paper on the employment of sheet mica (mineral isinglass) as a covering for wounds. I should like to call attention to the valuable uses to which this substance may be put, in war as well as in railway surgery.Block mica can be readily split to any degree of thickness, from several millimeters, as sold in the hardware stores, down to a thinness equal to the the finest Cargile membrane. Placed on the surface of a wound, its glassy texture renders it nonirritant and nonadherent, while at the same time the surface beneath can be viewed as under a glass. Thus, granulation tissue, bone repair, brain, nerve, tendon, intestine or other organic structure can be daily inspected, and changes, retrograde or reparative, noted without disturbance or exposure to infection of the area.