EARTHWORMS Blind But Useful

Auckland Star, Volume LXX, Issue 88, 15 April 1939, Page 7 (Supplement)

EARTHWORMS Blind But Useful

There will surely be none among our readers who needs an introduction to the common earthworm. Common and humble it may be, but it is also a very interesting and useful member of the animal kingdom, and well repays a little study.

To find specimens, or to watch the movements and habits of the earthworni in its natural surroundings, one does not need to go far afield. The type of soil which supports a plentiful

By---Olga P. Burton.

growth will probably also support a large number of worms; but practically any soil will be found to contain some specimens. They may not always be near the surface, however, for in frosty or very dry ■weather earthworms tend to descend as far down into the soil as several feet, in order to escape weather conditions in which they would not thrive. When such weather causes the worms to do this they regain dormant until the advent of conditions more to their liking. Emptying their bodies of surplus soil, these creatures when dormant curl themselves into coils which rest in little cavities excavated for the purpose.

Apart from actually seeing the elastic pink fellows, the simplest way of detecting their presence is by the observation of the familiar "worm casts"—the little heaps of earth thrown out at the mouth of the burrows. These "casts'' are composed of soil which has been eaten by the worms and which, during its passage through the bodies of the little animals, has had extracted from it certain elements which serve as nourishment. The diet consists largely of decaying animal and vegetable matter to be found in the soil, but besides this certain green food is also taken. The green leaf of the French bean has been found to be of considerable attraction, among others, and a brownish trail can sometimes be noted across a green leaf. This is the result and effect of the slime produced by the ■worm for the purpose of rendering the leaf material assimilable. As the worm possesses nothing in the way of teeth, it cannot chew; food to be taken, therefore, must be soft, so that it can be dealt with by the lips, and for this purpose this slime has the power of softening the leaf substance so that no chewing is necessary, the foot! being partly digested before the interior workings of the worm actually deal with it. The elime-marked trail of the worm can

sometimes thus be traced on the broad surface of a green leaf, for the effect of this secretion is to turn the leaf substance brown, thus marking the trail clearly from the rest of the leaf.

In connection with the matter of food it is interesting to note th:i : the earthworm has a sense of trncll which enables it to locate food. An acute sense of perception renders the worm very sensitive to vibration, and this fact' is probably of vital importance to a creature that is without the senses of sight and hearing— faculties of importance in the detection of approaching danger. Though lacking "eyes" in the usual sense, earthworms have a certain faculty, if it may so bo called, of distinguishing between light and darkness, as the skin—especially that of the front part of the body—is capable of sensing darkness and Tght. The shape of the worm is well known, though the series of muscular movements which enables it to alter its length—and, to a certain extent, its shape also—is always a fascination The tapering end of the body is the anterior or head-end, while the other end —the posterior —is somewhat broader and flattened. Such shaping is not haphazard, but serves a useful purpose /or the worm, for while the broad ta : l-end is able to remain in the burrow, anchoring the rest of the body. «o to speak, by its side pressure on the burrow walls, the tapering head-end can go exploring round about —wirhin a certain radiifs only, of course, while the other end is so fixed! At other times, too. when the worm goes further afield, the head-end, on the same principle as the point of a needle, can insert itself into small openings which gradually and with ease admit the rest of what is following after.

As is also the case with the colour of the surface of our own bodies, the earth worm gains its characteristic pinky-purple colour not from the coloration of the skin itself, but from the blood circulating beneath it. Here, too, the red colouring matter present in the blood serve* the same purpose—that of obtaining oxygen from the air in order that life may be maintained.

Something of the system whereby the human body is kept supplied with this very necessary substance is well known, and the lungs are an indispensable factor in the process. To the worm, however, lungs would be superfluous, for without them he manages very well indeed. He has no special breathing apparatus such as is of vital importance to most animals, but instead of having a s[>ecial system the worm is able to absorb the required oxygen directly through the frkin, which is very thin and is continually moistened by. the slime which the worm secretes.

Each of the many segments is supplied with a set of blood vessels, the purpose of which is to bring the blood near to the surface and this assist* in the direct absorption by the blood of the oxvgen from the outer air. Such a creature as the worm Wiouslv has no means of defence— in the ordinary sense of the termwhereby it mav be safeguarded to some extent from the many enemies met in the daily "crawl - ' of life. Ine slime already mentioned does, however, give some little assistance in this direction, as it makes the worm slipperv and therefore not easy to grasp "and hold. By this means it mav be seen to escape even from the clutches of the thrush; the lightning wav in which it can effect a retreat to the refuge of the burrow (provided the tail is securely anchored there) is undoubtedly another means of selfprotection. With a swift movement not unlike the relaxation of a piece of stretched clastic or indiarubbcr the worm thus darts back into safety.

This muscular method of manipulation enables the worm not only to retreat when necessarv, but it is also its means of progression. The rhythmic movements of parte or of Ihe whole lenglh of the worm as it moves along are full of fascination to the observer. Though certainly not

possessed of legs like a caterpillar or centipede the worm has been provided with a system of cdiort bristles on the underside, and as these grip on to any irregularities or iiiicxenness of surface as the worm crawls alonp they act as anchors for certain se£merits while the other segments following can draw themselves along. Kach of these many divisions of the body of the earthworm has eipht such bristle*, arranged in pairs, and though HOW-MAUVE DYE WAS DISCOVERED. Many girls who read our pages may have mauve frocks or frocks with mauve trimmings, but not many people know how this fashionable colour was really discovered.' William Henry Perkin, who died in 1907, was the man who gave us this, and many other, pretty colours. He devoted all his spare time, Including his evenings, to chemistry, carrying out his experiments in a rough, homemade laboratory. When he was trying to make quinine he hit upon mauve dye. Queen Victoria liked the colour, and she had a dress dyed with it. And so the new shade rapidly came into fashion. This laid the foundation of the coaltar dyes and the dye industry, which was afterwards founded, assumed very larjre proportions, becoming very important, and creating work for thousands of peoule.

their existence might never be even suspected by the casual observer their importance in the make-up of the worm Is considerable. «

Frequently we hear allusions to the worm which make it appear that this is indeed the least of creatures. "I felt an absolute worm," soniecne will tell vob, in such a tone as to make it verv clear that his or her opinion of the" worm is certainly not very high. Yet, like the ant and other inconspicuous, humble members of the animal kingdom, the worm is not so insignificant after all. if we but take the trouble to inquire a little into its habits. Silently ami without the least display, the earthworm continues a work whxh is of immense value to the soil, an J therefore to us all. for we are all dependent upon products of the soil.

It ha* been calculated that the number of worms estimated tn inhabit an acre of average quality soil (about 30,000 of them) bring to the surface an annual grand total of abotit 2S tons of soil; thus a amount of soil that might otherwise not be turned over or brought to the surface in years finds its way to the air and sunlight, where the sweetening action makes it more suitable for agricultural purposes.

Besides this, the burrows made by the worms in the course of their daily lives serve a useful purpose in the ventilation of the soil allowing air to penetrate and to become available to the roots of plants and also preventing the ground from becoming too waterlogged. So when next you feel "a mere worm" you may comfort yourself with the thought that the worm is not such a useless, despicable creature after all! Perkins became a great man, receiving many English and foreign honours. He was knighted in 1906, but he died the following year. AN ISLAND YOB CAN MOVE. Imagine living on a floating island! When a new 151-mile long lake above the Great Coulee Dam in the United States is completed, men who have helped to construct it will be able to tell stories about the times they spent on an island you could move. They will live on two huge floating camps, each to house 50 men, and each with a barracks, kitchen, dining room, workshop and tool house. The idea of these floating houses is that they will be towed all over the lake by "a C4ft tug. So. when work has to be done at a certain point, the sturdy little tug will come along, take the men to where they are needed, and when they have finished work at that spot it will tow their homes to another point where their services are needed.