The protection is less perfect about the hairs and the sweat glands.

Infection by the route of the sweat glands is, however, uncommon, for the sweat is a fluid unfavorable for bacterial growth and the flow acts mechanically in washing away organisms which may have entered the ducts.

Infection by the route of the hair follicles is common.

There is no mechanical cleansing as by the sweat, the space around the hair is large and the accumulated secretion of the hair glands and the desquamated cells furnish a material in which bacteria may grow.

Growing as a mass in this situation, they may produce sufficient toxic material to destroy adjacent living cells and thus effect entrance.