Semi-permeable suits were then prepared, in which the cotton sheeting was impregnated or coated with a solution of gelatin and glycerine. The fabric was then “tanned” to render the gelatin insoluble in water. Such a suit is valuable for factory wear, but the impregnating material is easily leached out and the suit is therefore not recommended for field service. This was built with an inside layer of dry cloth together with an outside layer of treated cloth to afford the necessary chemical protection against mustard gas. Work of fabrication consisted in treating the cloth with simplexene, cutting the suits to design and size, and sewing them together. Treatment consisted in passing the fabric through a dye machine, then through the wringer rolls where the excess oil was expressed. The inner layer of dry cloth was found necessary, since the cloth was cut as soon as treated. Simplexene does not attain the maximum degree of “tackiness” for two or three days, owing to the presence in the oil of a small amount of volatile spirits. However, by allowing the cloth to air for 48 hours before cutting, the inner lining could probably be dispensed with. The fighting suits were distributed among various detachments using mustard gas in field tests, and in other places where protection against vapor was needed and where field conditions were approximated. The tests showed that the suit gave satisfactory protection for considerable periods against mustard gas vapors. No other suit, equal both in porosity and protection, has yet been submitted, although samples furnishing better protection with much higher resistance have been examined. The protection of the simplexene suit is about 30 minutes against saturated gas. A large number of these suits were made and taken abroad for field tests at the front. PROTECTIVE GLOVES Protective gloves have been made with a variety of impregnating agents. The one which was selected for large scale production was impregnated with a solution of cellulose nitrate because of the availability of materials and the protection offered by the finished product. The material is impregnated after being made up. The one finger type of glove is used. The gloves are placed on wooden forms and dipped into the impregnating solution. After draining a few minutes, the gloves are turned upside down on racks and run through a drying oven. Finally they are removed from the forms and conditioned by drying at a moderate temperature for several hours. After being properly cured they are fitted with two straps on the gauntlet of each glove. They should offer protection to chloropicrin (standard method of test) for 30 minutes. When subjected to rough work they will last from one to two weeks. [Illustration: FIG. 81.—Coated Gloves for Protection against Mustard Gas.] PROTECTIVE OINTMENTS