The most common causes of blistering are friction, pressure or impact. Accessory causes are ill-fitting shoes and socks, overriding toes, hammer toes, poorly constructed un-even cheap shoes, heat, moisture, and uncleanliness. They are most often found in those whose foot skin is tender and soft, e.g, among newly recruited troops and those not accustomed to long hiking. The points usually affected are: the outer surface of the little toe, the upper surface of the toes, surface and back of the heel, an upper surface of a foot under the shoe-laces, a ball of the foot and over the Tendo Achilles (the large tendon attached to the upper surface of the heel bone). The formation of blisters is a protective process. Irritation of the outer or false, and inner or true skins being continuous, there arises an inflammation of both, during which, the inner skin exudes an inflammatory fluid and raises the outer thus forming a blister.

Treatment is directed primarily toward the cause. Inspect and remedy defects in the shoes or socks, such as nails, fallen toe cap, ill-fitting insoles, worn lining, tight lacing, uneven stitching as over the Tendo Achilles posteriorly and badly worn, darned, small or dirty socks. Apply to blister tincture of iodine 3,1,2 per cent. or grain alcohol. Immerse needle in alcohol or heat in flame and puncture at the base, allowing fluid to escape and covering (outer skin) to collapse on the inner or true skin thus protecting the latter and minimizing infection (invasion of microbes). The blister (outer or fals*e skin) should, therefore, not be torn or removed.

Dry the skin with gauze or absorbent cotton and cover the blister with adhesive plaster which should be firmly pressed down so that the raised outer skin or epidermis will be forced into position. The adhesive ma', be made to stick well by heating it with a match or applying either if the latter is to be had. Should it be impossible to procure adhesive plaster, then sterile vaseline, boric acid ointment or zinc oxide ointment may be applied with benefit. If these last-named articles are at a premium, the regulation foot-powder may be dusted on the part and a few turns of a gauze bandage made. All the dressings being completed, a moderate amount of the foot powder should be dusted on them and in the shoe. The powder prevents the edges of the adhesive from adhering to the sock and lessens friction in the shoe cavity, Too much powder is just as bad as none at all as a large quantity', tends to cake and form uneven surfaces. Search should 1w made for all areas which are red and tender with no formation of blisters. Adhesive pla.ss er should he placed over these.

Heel blisters occupy such a prominent place in the category of transient foot ills that they sh, add lie given careful attention.Usually caused by bad socks or poorly constructed ill-fitting shoes allowing the heel to slip, they form by far the great majority of blisters. The structural defects of the shoe are usual!. 1, such as (a) heel too narrow or broad (b) shoe too long (c) shoe too broad across the instep with high heels (d) incorrect posterior curve of the shoe not conforming to heel and tendon and (e) improper lacing. In the individual with a long, narrow foot and narrow heel, or the one with a broad foot and narrow heel. Many benefits can be derived by placing a felt pad varying in thickness, corresponding to the tongue of the shoe in size and posterior to it. The greater part of these blisters will be as provided by a proper measurement and fitting where the heel is regarded with more care. The figure-of-eight marching strap, originally devised and used by the French, will prevent the heel from slipping up and down, on the march in the great majority of cases. Abrasions are nothing more or less than blisters with the raised outer skin or epidermis removed exposing the rose red derma or inner skin. They are very painful due to the fact that the sensitive nerve endings in the derma or inner skin are unprotected and exposed to changes of temperature and injuries. In the blister, on the other hand, these nerve endings are protected by the raised epidermis and accumulated inflammatory fluid. The causes of abrasions correspond to the causes of blisters. The treatment is primarily corrective, The cause should be sought for and .remedied. Protective treatment includes the applying of alcohol (grain) or iodine 3% percent. to the area then zinc oxide adhesive plaster. In lieu of the adhesive plaster zinc oxide or boric acid, the ointment may be applied plus a few turns of a gauze bandage. In the prevention of blisters and abrasions there are three factors which determine the functional integrity of the foot:

1. Proper measuring of feet and fitting shoes

2. Proper corresponding sockā€”size.

3. (a) Feet inured to hiking or

(b) prepared for such.

The proper measuring of the feet and accurate fitting shoes together with the correct corresponding sock size will be discussed in full later. That foot inured to hiking will escape many injuries is self-evident. At this point, however, should be mentioned the application of formaldehyde Sol. 10 per cent. on alternate days for six applications to the soles of the feet and especially points exposed to pressure. This serves to harden the skin and lessens the chance of inflammation. Adhesive plaster may be placed over suspicioned pressure points before the march to escape the formation of blisters together with the same weight socks the shoes were fitted with.