…Some years ago the English neurologist Henry Head and his co-workers showed that the glans of the penis lacks the receptors of fine sensory discrimination ― light touch, small gradations of warmth or cold ― what Head called the epicritic sensations. The glans conveys only protopathic sensations: of deep pressure, extreme heat or cold, and pain. That is, the glans responds only to coarse stimuli, yet with sensations that possess what Head spoke of as great “affective tone,” whether exquisite pleasure or acute discomfort. The foreskin, however, like most other skin, has all the apparatus of fine as well as coarse sensory discrimination; and removing it takes away a considerable area of delicately responsive sensory surface.
The foreskin also provides a protective sheath for the glans, keeping its skin moist and tender. Its removal exposes the glans to the constant abrasion of clothing and keeps the skin dry. Hence the skin of the glans grows tough and coarse, with a further loss of sensitivity. Through both these effects, circumcision results in an appreciable loss of sensitivity and responsiveness of the male member.”