The human foot and the human hand

by George Murray Humphry

There are also in the skin a number of little Glands. One set of these are called “oil-glands;” for their office is to furnish an oily, or waxy, substance, which serves to keep the skin soft and pliable, and defends it against too much moisture, or too great dryness of the atmosphere. They are usually, as shown in the accompanying sketch, (fig. 83, g, g) connected with the hairs, lying beside them; and their ducts—the little tubes that carry off the oily matter formed in them—open either into the hair follicles, or penetrate the cuticle at some other part. They are not found on the palms of the hand or the soles of the feet, because those parts are, in great measure, sheltered from atmospheric influences, and are well moistened with perspiration. When the dry easterly winds prevail one is disposed to wish that these glands were more numerous on the back of the hands; for a more liberal supply of their secretion would, probably, prevent the disagreeable chapping to which we are subject at those times. As a substitute we resort to some unctuous matter, such as glycerine, which if frequently applied in small quantities performs, to some extent, the part of the natural secretion in keeping the cuticle soft and supple, and so preventing its cracking.

The secretion of these glands has an odour, the purpose of which, in man, is not very obvious. It is faintest in the highest and most civilized nations. In none is it very agreeable; and persons are fain to conceal it by substituting some other odour, as that of lavender or eau-de-cologne. Unfortunately the choice is not always so refined; and one is, sometimes, disposed to think that the natural odour must be very bad, if the substitute be preferable. The odour varies at different parts of the body; it varies also in different persons, sufficiently to enable the acute nose of the dog to track one particular man among a thousand.

Sweat-glands.

To revert to the figure ([70]) at page 165, the little masses at g, g, are grains of fat lying in the meshes of the deeper strata of the skin, or in the structure just below it. And the little balls of twisted tube (f, f) are Glands that secrete the Perspiration; for, the perspiration does not ooze up from the whole surface of the skin, but has a regular system of factories for its formation. A fine tube (h) is seen passing from each of these “sweat-glands,” as they are called. It curls in a spiral manner, like a cork-screw, where it traverses the cuticle to open at the surface. On the palmar aspect of the hand most of these tubes or ducts open along the tops of the fine ridges which are there seen; and with a magnifying glass of moderate power you can distinguish their orifices on the flattened tops of the ridges on your own fingers. These are the “pores of the skin,” respecting which we hear so much, and through which the Roman Bath brings such streams from the subjacent glands.

The sweat-glands are scattered all over the body, but are especially numerous in the palm and in the sole; and the moisture issuing from them tends to keep the skin of these parts soft and moist, and so fitted for the reception of tactile impressions. The quantity of fluid furnished by them varies a good deal in different persons, and under different circumstances. In some persons it is habitually slight; and the hands feel dry and harsh. Or, what is equally disagreeable, it is superabundant; and the hands are habitually damp, perhaps, cold and clammy, staining the gloves and soiling everything they touch. In fever the perspiration is defective; and the dryness and heat of the palm are often the first symptoms of an accession of fever that attract the patient’s notice.

We all know that perspiration is usually increased by exercise, or by the application of warmth to the surface, as by the hot air in the sudatorium of the Roman Bath; and then, by its evaporation, it cools and relieves the body, and contributes to our comfort. We know, too, that it is liable to be increased by any thing that produces a depressing effect, and that it then induces an uncomfortable sensation, chilling the surface too much, and making it cold and clammy. Most of you have experienced the discomfort of the cold sweat caused by fright; and some of you may have felt the cold, clammy hand of one who was suffering under the shock of a severe accident or the prostration caused by the sudden onset of a dangerous malady. Why perspiration should occur under these very different conditions, producing, at one time, so much relief, and, at another, so much additional discomfort, it is not easy to say.

The sense of Feeling and of Touch in the Hand.

I have mentioned three parts of the body as remarkable for the acuteness of the sense of touch, namely, the Tongue, the Lips, and the Hands. Now in each of these the skin is richly supplied with nerves and blood-vessels; and it is also thick and lies upon a soft cushiony substance, so as to be yielding and to admit of being applied accurately over any surface with which it is placed in contact, and of again resuming its shape when the pressure is removed. For instance, the tongue is so soft and yielding that, when it is applied to a tooth, it dips down between the inequalities and coves accurate information of the condition of the whole surface. The same is the case with the edges of the lips, though not in so marked a degree as in the tongue; and each of these parts is indebted for its great sensitiveness very much to the delicate soft supple nature of its structure. The palmar surface of the hand too, though, like the skin of the sole, it is strong and tough, so as to offer considerable resistance to injury and to prove no dainty morsel even to dogs, as we surmise from the narrative of the death of Jezebel, is yet very soft and yielding. It is also underlaid by a stratum of fat interwoven with strong fibres of tissue, just in the same manner as the skin of the sole of the foot (fig. [46], p. 99).

An accumulation of this fat and fibrous tissue under the skin forms the “Pulps” at the ends of the fingers. The slightly conical form and exquisite softness of the Pulps adapts them well for the examination of the surfaces of bodies; and the sense of touch is more acute in them than in other parts of the hand.