An extensive study of this question was made both in the laboratories and on the field. At first it was believed that successful results could be obtained by the use of such ointments. Careful investigation showed, however, that while these ointments really did protect against rather high concentrations of vapor for short times of exposure, they were probably not so valuable when used against low concentrations over an extended period of time. It was further demonstrated that the protection furnished by a coating of linseed oil is practically equal to the best ointment which has been developed. About 150 ointments were prepared and tested. These consisted of two parts or components, the metallic soap or other solid material and the oil or liquid part which bound and held the solid. The latter is called the base. The best base is lanolin, containing 30 per cent of water. A solution of wax in olive oil was next best. Of the metallic soaps the oleates and linoleates are better than the stearates. A satisfactory ointment has the following composition:
| Zinc oxide | 40 |
| Linseed oil (raw) | 20 |
| Lard | 20 |
| Lanolin | 20 |
A modification of this formula is:
| Zinc oxide | 45 |
| Linseed oil | 30 |
| Lard | 10 |
| Lanolin | 15 |
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.