136 TRICIloLOfUA MAMMALFCM: 



brium of bodily temperature. For this purpose pile has been formed, a non-conductor of 

 caloric. The " downy hairs" distributed over our bodies cannot be expected to contribute 

 largely to this end ; and, consequently, we find that whenever a part of the person 

 requires more than ordinary protection from cold, a greater abundance of hair is produced. 

 Hair may also have been intended to preserve the epidermis from the injurious effects of 

 too much friction, from contact with hard external objects ; each hair, upon such occasions, 

 acting the part of a friction rotter. This may, also, be one of the uses of the long hairs 

 found, still more plentifully upon the head, body and limbs of some of the lower mam- 

 malia ; they prevent their wool, which is underneath, from being torn out by the roots, 

 and their skin from being lacerated in their daily rambles through forests, their clamber- 

 ing up trees, and their burrowing in the earth. The Mole (Tatpa Europea,) has a short, 

 soft, smooth fur, offering little or no resistance or adhesion to the moist earth, through 

 which he bxirrows ; and it is a coincidence, no less remarkable than instructive, that the 

 insect, "Mole Cricket,'" (Gryllo Talpar,) who works his way under ground in the same 

 manner, is covered with a fine down, which has corresponding properties. In the order 

 " Pachyderrnata," such as the Elephant, Rhinoceros and Hippopotamus, the skin is so 

 thick and tough as to be impregnable, and no protecting hairs are required ; and, therefore, 

 nature (who never labors in vain) has provided none.* If man has fewer hairs upon his 

 body, generally, than some of the lower animals, he is, consequently, less impeded than 

 they are in the refined sense of feeling, possessed through the dermis and epidermis ; a 

 sense so necessary to his enjoyment, but which would be an incumbrance to inferior classes 

 of animals. At other times hair is accumulated to act as a cushion of protection, as in the 

 case of that of our heads, where it acts, in concert with the bony fortress of the skull, to 

 preserve the brain from external injuries.! 



Another use of pile to the animal, is to protect the part upon which it is produced from 

 the injurious effects of superabundant moisture ; the hair collecting the fluid and repelling 

 it from the part. Insects which, like gnats, walk upon the surface of water, have, at the 

 extremity of each foot, a brush of fine, hair-like processes, (which, however, are not 

 true hairs,) the dry points of which repel fluids and keep the fool and leg dry. And some 

 of the hairy-footed mammalia, who inhabit the water, are provided with a still further 

 means of protection from the action of moisture, by an adipose secretion, with which this 

 tegumentary appendage is profusely anointed. 



Hair, being electric, subserves the purpose of attracting that fluid from the atmosphere, 

 thereby keeping up a healthy circulation and preserving a proper equilibrium, notwith- 



* The few hairs found in the Elephant's ear, and on his jaw and tail, are noticed in another place. 



f The hair of the head deadens the concussion which the brain would experience from the infliction of heavy blows ; and pre- 

 vents the skin of the scalp from being injured by the attrition of bodies. In military service the former of these uses has been 

 taken advantage of, and an arrangement somewhat similar to that which exists naturally on the head, has been adopted with 

 regard to the helmet. The metallic substance of which the ancient and modern helmets are formed, is readily thrown into 

 vibrations, which being communicated to the brain, might, after heavy blows, derange its functions, more even than the wound 

 inflicted by a sharp instrument. To obviate this, the helmet is covered with horsehair. This arrangement prevailed with the 

 Human soldier. (Dunglison Hum. Physio., 55.) 



