The physical properties of this ointment are very good. It forms a smooth, even coating on the skin, sticks well enough not to rub off easily on the clothing and yet is not sticky. Its consistency is such that it can be readily pressed from an ointment tube. A. E. F. reports indicate that sag paste (zinc stearate and vegetable oil) is as satisfactory as any of the preparations tried. The great difficulties of such preparation from a field point of view are: Extra weight to be carried by the soldiers, necessity for keeping in tight boxes or tubes, thereby adding to the difficulty of carrying, and finally, the difficulty encountered when applying it properly to the body in the field, where gas contaminated hands may cause harm. The paste was too late a development for thorough field trial. It was used just enough to cause severe partisan controversies between its advocates and those opposed to it. Unquestionably, it proved of decided value in preventing mustard gas burns when properly applied. There are many authentic cases where men alongside each other were similarly gassed except as to burns. The difference in burns arose from the use or non-use of the paste, and in some cases of poor application. Fries is of the opinion that had the war lasted another year the use of pastes would have become universal unless some thoroughly successful substance for impregnating the uniform or underclothing had been developed. This is likewise his belief for the future. PROTECTION OF ANIMALS =Horse Mask.= The need of protection for animals (horses and dogs), although not as great as in the case of men, was of sufficient importance so that masks and boots were developed for the horse and a mask for the dog. The German horse mask was the first produced. It was of the nose bag type, enveloping the mouth and nose of the animal. It was fitted with a complicated drawstring and with snap hooks fastening it to the harness. The interior contains a plate of stiff material to prevent the collapse of the bag. The mask itself was apparently not impregnated, but was used wet or with a filling of wet straw or rags to act as the absorbent. [Illustration: FIG. 82.—German Respirator for Horses.] The French had two types of horse masks impregnated with a glycerine-nickel hydroxide mixture. One type had a closed bottom, while in the other, the bottom was open. The British horse mask has a two-layer flannelette bag, with a canvas mouth pad and elastic drawstring. It was impregnated with a mixture of phenol, formaldehyde, ammonia, canister soda and glycerine.