66 Life and Immortality. 



Two ways are adopted by worms in excavating their bur- 

 rows. Either the earth is pushed away on all sides or it is 

 swallowed by the animal. In the former case the worm 

 inserts the stretched-out and attenuated anterior extremity 

 of its body into any little crevice or hole, and the pharynx 

 is pushed forward into this part, which consequently swells 

 and pushes away the earth on all sides, the anterior extremity 

 thus acting as a wedge. When placed in loose mould a worm 

 will bury itself in between two and three minutes, but in 

 earth that is moderately pressed down it often requires as 

 many as fifteen minutes for its disappearance. But whenever 

 a worm burrows to a depth of several feet in undisturbed 

 compact ground, it must form its passage by swallowing the 

 earth, for it is impossible that the ground could yield on all 

 sides to the pressure of the pharynx when pushed forward 

 within the worm's body. Great depths are reached only 

 during continued dry weather and severe cold, the burrows 

 sometimes attaining to a depth of from seven to eight feet. 

 The burrows run down perpendicularly, or, more commonly, 

 obliquely, and are sometimes said to branch. Generally, or 

 invariably as I think, they are lined with fine, dark-colored 

 earth voided by the worm, so that at first they must be made 

 a little wider than their ultimate diameter. Little globular 

 pellets of voided earth, still soft and viscid, often dot the 

 walls of fresh burrows, and these are spread out on all sides 

 by the worm as it travels up or down its burrow, the lining 

 thus formed becoming very compact and smooth when 

 nearly dry and closely fitting the worm's body. Ex- 

 cellent points of support are thus afforded for the minute 

 reflexed bristles which project in rows on all sides from the 

 body, thus rendering the burrow well adapted for the rapid 

 movement of the animal. The lining appears also to 

 strengthen the walls, and perhaps saves the worm's body 

 from being scratched, which would assuredly be the case 

 when the burrows, as is occasionally observed, pass through 

 a layer of sifted coal cinders. The burrows are thus seen to 



