August 1, 1889.] 



♦ KNOWLEDGK ♦ 



203 



pression of the size and shape of surrounding objects. Their 

 sense of smell is shown in the choice and selection of dif- 

 ferent kinds of food. Cabbage-leaves and bits of onion, 

 buried Ijeneath a |inch of earth, were almost greedily run 

 after ; the worms in well nigh every instance discovered 

 them, and dragged them out. As you might fairly expect 

 in an animal so comparatively omnivorous as the earth- 

 worm, he possesses a very decided sense of taste. Onions, 

 cabbage, the common or garden green cabbage especially, 

 are liked by them. Celery they devour seemingly with a 

 relish. They also manage to swallow an enormous quantity 

 of earth. They don't object to liquorice. They don't mind 

 whether their meat is cooked or raw ; but, above all else in 

 the meat line, a bit of raw fat seems to titillate theii- palate 

 most. Cannibals are they, for they will gnaw away 

 unconcernedly at the half of a dead brother's body ; 

 but you cannot expect much sentiment in an animal 

 with only two cerebral ganglia to lepresent its brain, 

 and six pulsating arteries for a heart. Their digestive 

 fluid differs in no respect from that of higher 

 animals : it acts on fat, on the fibrin of meat, on starch, 

 and on the cell-walls of leaves and other parts of plants, 

 a very useful thing, you can imagine, for an animal 

 which lives chiefly on half-decayed leaves, whereof the 

 cell-walls are almost three-fourths of the nutriment, for of 

 course the meat diet is not obtained save by one in a thou- 

 sand, who happens to fall in with a kindly collector. Earth- 

 worms take kindly to milk, in which it would be a good 

 thing if more of mankind imitated them. Also it is in- 

 teresting to note that the secretion wherewith worms 

 moisten the leaves they di-ag into their burrows partially 

 digests them, which may remind us of the digestion of flies, 

 &c., on the leaves of the sundew. 



The distribution of earth-worms is wide, almost universal. 

 In England they inhabit the commons and chalk-downs as 

 well as the London parks, with their diflereut qualities of 

 soil. In the grassy paths across moors they abound, and in 

 paved courtyards you may often come across evidence of 

 their presence. Their castings have been found at various 

 heights from 1,500 to 4,000 feet above the sea, on Schiehallion 

 in Scotland, on some hills near Turin, and on the Hima- 

 layas. You count them terrestrial animals, that is, animals 

 which inhabit the earth, though they have been kept .alive 

 for nearly four months completely submerged in water. 

 Also they want a damp air to live in, as was proved by 

 exposing some to the dry air of a room for a single night : 

 in the morning they were all dead. A few remarks here on 

 their relations and the class to which they belong seem to 

 fall in naturally. One, almost the nearest, of their relations 

 is the leech — everyone knows the medicinal one, if they do 

 not know the common horse-leech of ponds. Then there 

 are fresh- and salt-water worms. When you examine the 

 latter, which genei-ally secrete a tube wherein thcsy 

 dwell, such as the beautiful Serpula, with its crown 

 of tiny ostrich feathers, you find they have a special 

 apparatus — the gills — whereby they breathe. Most 

 people must have seen the coils of sand which are so 

 frequent between high and low water-mark on the shore, 

 and to explain whose construction saintly or demoniacal aid 

 has been invoked. These ai-e the casts of the lug-worm, 

 greatly in demand for bait. Then the free-swimming 

 Nereids, as they are prettily called, are worms of wonder- 

 fully exquisite colour, changing with each movement of the 

 animal. The sea-mouse, Aphrudlte, too, comes near to these, 

 with its hairy coat sparkling in the sun with every 

 imaginable play of (colours. Jt is also notable as having 

 gills of rather curious construction on its l)ack, acting some- 

 what like the respirators wherewith people try to mitigate 

 the piercing chill of a " wild north-easter." 



Most families, if not all, have, they say, some poor relations, 

 or, if not exactly poor, so disreputable that they never mention 

 them. The earthworms are no exception to this rule. Their 

 parasitic relatives must not be mentioned to ears polite. 

 That word parasitic recalls something about the leech. You 

 may count it as a parasite, since it lives on the blood of 

 other animals, and as such obeys the same laws as other 

 parasites. In common conversation, when we call a man a 

 parasite, we mean to imply that he is a degraded being : 

 it is much the same among animals. You will almost 

 universally find that a parasitic animal has become de- 

 graded from what is lielieved to be his original position in 

 his class. Somewhat in the same way as an endowment or an 

 assured position has been the ruin of many a man who might 

 have turned out a fine specimen of humanity if he had had 

 his own way to make in the world ; so, when your animal 

 gets a gi-eat deal of the work of procuring and preparing 

 food done for him, he gets lazy and sinks lower in the scale 

 of animal life. The neighbouring classes to the earth-worms are 

 lowest of all the Protozoa, already mentioned, containing the 

 Atnmha, Ophrydvimi, and the like. Then the Ccelenterata, 

 with Hi/dra, the sea-anemones, and the jelly-fishes. Next 

 we get to the Echinoderms, some of which are known much 

 better by their commoner name of star- fishes. Our earth- 

 worms and theii' relations form the class above ; while just 

 above them, in turn, come the Arthropods, including 

 lobsters, centipedes, spiders, and insects. Above them, 

 again, are the mollusks, the fresh-water mussel, the oyster, 

 and the common snail. 



Now to turn to a more interesting part of my subject — 

 the habits of eai-th-worms. I mentioned that their upper 

 lip was useful for seizing articles of food ; they take hold of 

 the edge of a leaf, for example, between the upper and lower 

 lips, with a very firm grasp. But when they have to deal 

 with broad flat objects, they act in a totally different way. 

 The anteiior end of the body is, withdiawn a little within 

 the first three or four segments, so as to form a flat end to the 

 body ; this flat end, something like the end of a pencil-case, 

 is then applied to the cabbage- leaf or a slice of onion, and a 

 vacuum is produced whereby the worm gets a tight hold of it. 

 Worms are fond of leaves, not only as food, but also to use 

 for plugging up the mouths of their burrows, and for lining 

 their walls, probably so as to protect their bodies from the 

 cold earth around. They also protect the mouths of their 

 burrows with little heaps of stones, which they di-ag from 

 some distance — by .suction as well. Air. Darwin thought 

 these plugs were apparently to keep out the cold air, and to 

 keep the air already within thoroughly damp, which, as we 

 have seen, is essential to a worm's happiness, and even to 

 his existence. Now the manner in which these loaves were 

 dragged into the burrows is interesting. As the tip of a 

 leaf is generally the smallest and narrowest part of it, pro- 

 bably if you or I had to use these leaves for wall- 

 papers in our " diggings," we shouUl drag them in 

 by the tip. Mr. Darwin examined over two hundred 

 leaves of dilTerent kinds which had been in the earth- 

 worms' burrows, and nearly eighty out of each hundred 

 had been dragged in by the tips. A good number 

 of these were leaves of the lime, which are very 

 pointed at the top, and gradually swell out to a broad 

 base with a well -developed foot-stalk. The i-est of these 

 leaves were draw-n in partly by their base, partly by 

 their middle, — probably the stiflness of the leaves had a 

 great deal to do with this latter portion. Then Mr. 

 Darwin tried the leaves of laburnum, which are quite as 

 pointed at the base as at the tip ; and the worms dragged a 

 good many more of those in by the base, nearly thirty out 

 of a hundred. But still, the larger p.art by far were dragged 

 in by their tips, showing that worms have probably acquu'ed 



