ï~~VOLUME 71 THE ARMY NUMBER 15 of the mask is the inspiratory suction through the mask. The same series of masks were used although only one quality of gauze was completely worked out. This was the Lakeside (24 by 20). Five layers were necessary to protect the plate completely, which amount represents 220 strands of cotton fiber to the square inch. A third series of tests were made with duplicate masks; one was placed over the face and one over the exposed plate, each succeeding mask being increased in thickness by one layer of gauze. The series embraces all thicknesses from one to eight. The gauze used for the series was Lakeside (24 by 20). The figures obtained tend to show that cotton fibers in superimposed layers of gauze to the extent of 350 to, the square inch equally divided between the infected and uninfected will prevent droplet infection. This result may be interpreted as inebnsistent with the figures of the protocol given. This apparent inconsistency is, we believe, quite within the limit of error of the methods used. It can be shown that the mask over the face of the infected is of value in the prevention of the uninfected when used in addition -to the mask over the plate which represents the uninfected. Experiments made with washed gauze demonstrated the following facts: The better qualities of gauze B and B (32 by 26), L and L (.28 by 24) and Lakeside (24 by 20) become more efficient through shrinkage of the fiber, and if too thick at the outset become almost unbearable after repeated washing. Here also there is some question whether or not most of the respiratory exchange takes place about the edges of the mask, rather than through it. With the very poor quality of gauze, Dearborn (20 by 14), there is a decided tendency for the gauze to pull apart and leave very large gaps in the individual layers. We are of the opinion that this gauze should never be used for this purpose. Work with the reknit gauze has demonstrated that it is almost impossible, because of its remarkable. stretching, to estimate its efficiency. Even under ordinary conditions it does not remain the samefor more than a few minutes at a time. We hesitate to recommend its use, as we have seen a thick mask so stretched out and thinned after an hour's wear that it was quite obviously useless. A small amount of work was done with Turkish toweling. Preliminary experiments tend to show that one layer of this material makes a highly efficient droplet filter, and it is comfortable to wear. The question of expense, and also the question of the effect of wear on this material, are to be considered. SUGGESTIONS FOR MASKS 1. It is our belief that gauze of the;quality. of Lakeside (24 by 20) or L and L (28 by 24) should be used in four layers, B and B (32 by 26) in three layers, provided all persons are masked. In case only the infected are masked, Lakeside (24 by 20) should be seven layers thick, L and L (26 by 24) six layers, and B and B (32 by 26) five layers. If the masks of this thickness are used, the ambulances and receiving offices and particularly the clothing of uninfected patients would probably not become infected. 2. Masks should be 8 inches in length with the edges turned in and stitched. They should be 5 inches in width. SHOE-RUGH '.215 3. Two braids should be used, each 1 yard long and sewed along the upper and lower borders of the mask so as to leave a free end 14 inches long at each side. 4. The masks should be marked on the face side by a black thread tied in the gauze. THE ARMY SHOE AND MILD FOOT DISABILITIES J. TORRANCE RUGH, M.D. Lieutenant-Colonel, M. C., U. S. Army. PHILADELPHIA Extensive foot inspections were made of the soldiers who were trained during the latter half of 1917 and early part of 1918. These inspections were first made,when the men were inducted into service and while the feet still showed the abnormal conditions that were present in civil life, and again before they were sent overseas. Comparison of the results of the two examinations disclosed that marked changes had occurred, and the experience of civil orthopedic practice is verified by these observations. These changes have been almost uniformly favorable to better function of the feet, and when unfavorable results have occurred, the reason has been readily traced. In endeavoring to account for the marked changes observed, there are two factors that stand out as most potent. First is the Army shoe and second is the increased personal care and interest in foot health on the part of the officers and men from the instruction by the orthopedic surgeons. Extensive observation (covering several hundred thousasd cases) shows that 98 per cent. of the recruits can be fitted with the Army shoe. This fact alone is the strongest possible recommendation for its use, but an additional fact still more strongly recommends it. This is the beneficial influence of the shoe on the foot of the wearer. When a shoe is properly fitted at the beginning of service, there should be about twothirds inch between the end of the longest toe and the end of the shoe. After from four to six months of training there should be at least half an inch. The heel should be held fairly snug in the shoe, the vamp should fit smoothly over the forefoot, and the ball of the foot should rest in its seat near the posterior turn of the sole. In fitting shoes, it must always be remembered that a shoe will enlarge sidewise but never lengthwise. Also, that repairing tends to shorten a shoe, and rebuilding actually does shorten it. Short shoes cause more foot troubles than narrow ones; hence the great need of the two-thirds inch room in the length of the shoe to accommodate the lengthening of the foot in the first four or five months of training. This length and breadth of shoe permits a degree of function hitherto unknown to the foot. There is greater freedom of toe action, which affects both muscles and joints. This is followed directly by lengthening of ligaments, increase in size of muscles and alteration of relations of all the anatomic elements of the foot. These factors contribute directly to an increase in the size of the part. I have repeatedly seen cases in which the original size of the shoe had been strongly objected to as being entirely too larg'e, but after a few months of intensive training and perhaps using extra or thicker socks, the fit was entirely satisfactory by reason of the development of the foot.