+Talipes Cavus+ (Pes Cavus), or hollow foot, is a condition in which the arch of the foot is greatly exaggerated. It is rarely congenital but is frequently seen in connection with clubfoot, especially in its paralytic forms. In its mildest form, it exists in a highly arched foot, often hereditary. It may also be the result of too short shoes (Chinese ladies’ foot). +Treatment.+ The condition is best remedied by division of the contracted soft parts, a forcible reduction of the bones, held in place by plaster of Paris. When the patient begins to walk, it is advisable to have a stiff, flat, steel plate placed in the length of the shoe between the layers of the leather sole, running from which, over the dorsum of the foot, is a stout leather strap. At each step, downward pressure is thus exerted on the dorsum of the foot. CHAPTER XVIII +THERAPEUTIC MEASURES+ +HYPEREMIA+ +Hyperemia+ as a therapeutic agent was described by Bier and is of two kinds, _active_ and _passive_. The former is the same as the _arterial_, while the latter is the _venous_. Between the blood of active and passive hyperemia there are important physical and chemical differences, the one containing much free oxygen with but little carbonic acid and alkali, while the other presents the exactly opposite character. In active hyperemia normal elements of the blood are kept in active motion, while in the passive form they are allowed to escape, more or less, into the tissues. Hyperemia possesses a great many properties: 1. Power to diminish pain. 2. Bactericidal action. 3. Absorptive property. 4. Solvent action. 5. Nutritive power. 6. Suppression of the infection. Hyperemia may be produced in three ways; _first_, by means of the elastic bandage or band; _second_, by cupping glasses, and _third_, by hot air. The first two produce venous or passive hyperemia, and the third, arterial or active hyperemia. +Passive Hyperemia.+ This obstructive hyperemia is produced by means of a thin, soft rubber elastic bandage, two or three inches in width, better known as the Esmarch, or Martin bandage. When this is applied moderately tight around a limb about six or eight turns, one layer overlapping the other, pressure is evenly distributed over a comparatively wide area, causing the subcutaneous veins below the constriction to swell; the extremity becomes somewhat bluish red in color, also larger and edematous, giving a feeling of warmth to the touch. The rubber bandage, properly applied, should not cause any uncomfortable feeling and there should be absolutely no pain present. At all times one must be able to feel the pulse below the site of the bandage. If the bandage is applied too tight, the skin of the limb looks grayish-blue and there appear whitish, or vermilion colored spots, which grow larger and larger, as long as the too tightly drawn bandage is on. Paresthesia and pain, with disappearance of the pulse, can also be noted.