Linn.) seems to know instinctively that worms will emerge if the ground is made to tremble; for Bishop Stanley states (as I hear from Mr. Moorhouse) that a young peewit kept in confinement used to stand on one leg and beat the turf with the other leg until the worms crawled out of their burrows, when they were instantly devoured.  Nevertheless, worms do not invariably leave their burrows when the ground is made to tremble, as I know by having beaten it with a spade, but perhaps it was beaten too violently.

The whole body of a worm is sensitive to contact.  A slight puff of air from the mouth causes an instant retreat.  The glass plates placed over the pots did not fit closely, and blowing through the very narrow chinks thus left, often sufficed to cause a rapid retreat.  They sometimes perceived the eddies in the air caused by quickly removing the glass plates.  When a worm first comes out of its burrow, it generally moves the much extended anterior extremity of its body from side to side in all directions, apparently as an organ of touch; and there is some reason to believe, as we shall see in the next chapter, that they are thus enabled to gain a general notion of the form of an object.  Of all their senses that of touch, including in this term the perception of a vibration, seems much the most highly developed.

In worms the sense of smell apparently is confined to the perception of certain odours, and is feeble.  They were quite indifferent to my breath, as long as I breathed on them very gently.  This was tried, because it appeared possible that they might thus be warned of the approach of an enemy.  They exhibited the same indifference to my breath whilst I chewed some tobacco, and while a pellet of cotton-wool with a few drops of millefleurs perfume or of acetic acid was kept in my mouth.  Pellets of cotton-wool soaked in tobacco juice, in millefleurs perfume, and in paraffin, were held with pincers and were waved about within two or three inches of several worms, but they took no notice.  On one or two occasions, however, when acetic acid had been placed on the pellets, the worms appeared a little uneasy, and this was probably due to the irritation of their skins.  The perception of such unnatural odours would be of no service to worms; and as such timid creatures would almost certainly exhibit some signs of any new impression, we may conclude that they did not perceive these odours.

The result was different when cabbage-leaves and pieces of onion were employed, both of which are devoured with much relish by worms.  Small square pieces of fresh and half-decayed cabbage-leaves and of onion bulbs were on nine occasions buried in my pots, beneath about ¼ of an inch of common garden soil; and they were always discovered by the worms.  One bit of cabbage was discovered and removed in the course of two hours; three were removed by the next morning, that is, after a single night; two others after two nights; and the seventh bit after three nights.  Two pieces of onion were discovered and removed after three nights.  Bits of fresh raw meat, of which worms are very fond, were buried, and were not discovered within forty-eight hours, during which time they had not become putrid.  The earth above the various buried objects was generally pressed down only slightly, so as not to prevent the emission of any odour.  On two occasions, however, the surface was well watered, and was thus rendered somewhat compact.  After the bits of cabbage and onion had been removed, I looked beneath them to see whether the worms had accidentally come up from below, but there was no sign of a burrow; and twice the buried objects were laid on pieces of tin-foil which were not in the least displaced.  It is of course possible that the worms whilst moving about on the surface of the ground, with their tails affixed within their burrows, may have poked their heads into the places where the above objects were buried; but I have never seen worms acting in this manner.  Some pieces of cabbage-leaf and of onion were twice buried beneath very fine ferruginous sand, which was slightly pressed down and well watered, so as to be rendered very compact, and these pieces were never discovered.  On a third occasion the same kind of sand was neither pressed down nor watered, and the pieces of cabbage were discovered and removed after the second night.  These several facts indicate that worms possess some power of smell; and that they discover by this means odoriferous and much-coveted kinds of food.

It may be presumed that all animals which feed on various substances possess the sense of taste, and this is certainly the case with worms.  Cabbage-leaves are much liked by worms; and it appears that they can distinguish between different varieties; but this may perhaps be owing to differences in their texture.  On eleven occasions pieces of the fresh leaves of a common green variety and of the red variety used for pickling were given them, and they preferred the green, the red being either wholly neglected or much less gnawed.  On two other occasions, however, they seemed to prefer the red.  Half-decayed leaves of the red variety and fresh leaves of the green were attacked about equally.  When leaves of the cabbage, horse-radish (a favourite food) and of the onion were given together, the latter were always, and manifestly preferred.  Leaves of the cabbage, lime-tree, Ampelopsis, parsnip (Pastinaca), and celery (Apium) were likewise given together; and those of the celery were first eaten.  But when leaves of cabbage, turnip, beet, celery, wild cherry and carrots were given together, the two latter kinds, especially those of the carrot, were preferred to all the others, including those of celery.  It was also manifest after many trials that wild cherry leaves were greatly preferred to those of the lime-tree and hazel (Corylus).  According to Mr. Bridgman the half-decayed leaves of Phlox verna are particularly liked by worms. [31]

Pieces of the leaves of cabbage, turnip, horse-radish and onion were left on the pots during 22 days, and were all attacked and had to be renewed; but during the whole of this time leaves of an Artemisia and of the culinary sage, thyme and mint, mingled with the above leaves, were quite neglected excepting those of the mint, which were occasionally and very slightly nibbled.  These latter four kinds of leaves do not differ in texture in a manner which could make them disagreeable to worms; they all have a strong taste, but so have the four first mentioned kinds of leaves; and the wide difference in the result must be attributed to a preference by the worms for one taste over another.

Mental Qualities.—There is little to be said on this head.  We have seen that worms are timid.  It may be doubted whether they suffer as much pain when injured, as they seem to express by their contortions.  Judging by their eagerness for certain kinds of food, they must enjoy the pleasure of eating.  Their sexual passion is strong enough to overcome for a time their dread of light.  They perhaps have a trace of social feeling, for they are not disturbed by crawling over each other’s bodies, and they sometimes lie in contact.  According to Hoffmeister they pass the winter either singly or rolled up with others into a ball at the bottom of their burrows. [32]  Although worms are so remarkably deficient in the several sense-organs, this does not necessarily preclude intelligence, as we know from such cases as those of Laura Bridgman; and we have seen that when their attention is engaged, they neglect impressions to which they would otherwise have attended; and attention indicates the presence of a mind of some kind.  They are also