It is common to find that the patient has been troubled for a long time
before the onset of definite signs of gangrene, with cold feet, with
tingling and loss of feeling, or a peculiar sensation as if walking on
cotton wool.
The first evidence of the death of the part varies in different cases.
Sometimes a dark-blue spot appears on the medial side of the great toe
and gradually increases in size; or a blister containing blood-stained
fluid may form. Streaks or patches of dark-blue mottling appear higher
up on the foot or leg. In other cases a small sore surrounded by a
congested areola forms in relation to the nail and refuses to heal. Such
sores on the toes of old persons are always to be looked upon with
suspicion and treated with the greatest care; and the urine should be
examined for sugar. There is often severe, deep-seated pain of a
neuralgic character, with cramps in the limb, and these may persist long
after a line of demarcation has formed. The dying part loses sensibility
to touch and becomes cold and shrivelled.
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