Nature's Teachings: Human Invention Anticipated by Nature

by J. G. Wood

To every joint there are attached certain glands that supply a kind of oily substance technically named “synovia,” which acts exactly the same part as the oil or grease of machinery. If these glands do not do their duty, and the supply of synovia be defective, the joints become stiff, painful, and crackle when they are moved.

Then, exactly as the joints of a machine become stiff from non-usage, so do those of a human being. We will take, for example, the Indian Fakirs who vow that they will not move some limb from a definite posture. At first the exertion is trying and painful, but by degrees the disused joints lose their faculty of motion, and, even if their owner wished to move a limb, he could not do it.

The right-hand figure of the illustration represents the lubrication of an ordinary sewing machine, and the left-hand figure is a section of the human knee-joint, showing the gland which supplies the synovia.

Perhaps some of my readers may think that such a subject as the “Lazy-tongs” is too trivial for a work which deals, however lightly, with science. But there may be some who know the inestimable benefit of Lazy-tongs under certain conditions.

There are many cases where a severe injury has occurred, or where rheumatism has fixed its tiger-claws in the joints, so that movement is all but impossible. There may be no one in the room to help the invalid, and even to stretch the arm over the table is as impossible as to jump over the house.

Then it is that the real value of the Lazy-tongs becomes manifested, and that it shows itself in the light of a supplementary limb. With a mere movement of the fingers it can be stretched across any table which is likely to be placed before an invalid, and seize the required object by the tongs at the further end.

The only drawback to its use is, that the instrument cannot be shortened without opening the tongs. But, if some plan could be devised whereby the tongs could retain their hold under those conditions, the instrument would be a perfect one.

Exactly such a Lazy-tongs we have in Nature, in the well-known “mask of the larva and pupa of the Dragon-fly.” It is called a mask because, when closed, it covers the face.

It chiefly consists of two flat, horny plates, hinged in each other like a carpenter’s two-foot rule, and being capable of extension to a considerable length. The end is widened, and furnished with two jaws, which take the part of the tongs in the instrument above described.