68 Life and Immortality. 



if spread out uniformly, would form in many places a layer 

 of one-fifth of an inch in thickness. But this large amount 

 is not deposited within the old unused burrows. If the 

 burrows did not collapse, the whole ground would be first 

 thickly riddled with holes to the depth of ten inches or 

 more, which in fifty years would grow into a hollow, unsup- 

 ported place ten inches deep. 



Hardly any animal is more universally distributed than 

 worms. The earth-worm is found in all parts of the world, 

 and some of the genera have an enormous range. They 

 inhabit the most isolated islands, abounding in Iceland, and 

 also being known to exist in the West Indies, St. Helena, 

 Madagascar, New Caledonia and Tahiti. Worms from 

 Kergulen Land in the Antarctic regions have been described 

 by Ray Lankester, and Darwin has reported them as being 

 foun'd in the Falkland Islands. How they reach such 

 isolated islands is quite unknown. They are easily killed 

 by salt water, and it does not seem likely that young worms 

 or their egg-capsules could be carried in earth adhering to 

 the feet or beaks of land-birds, especially to Kergulen Land, 

 for it is not now inhabited by any terrestrial bird. 



We have seen that worms are found in nearly every part 

 of the globe, that they are very numerous, as many as 

 348,480 having been found in an acre of rich ground in New 

 Zealand, and that by the peculiar economy of their nature 

 they are fitted to accomplish a great deal of good in the 

 earth. They have played a more important part in the 

 history of the world than most persons would at first sup- 

 pose. In many parts of England, according to Darwin, a 

 weight of more than ten tons of dry earth annually passes 

 through their bodies and is brought to the surface in each 

 acre of land, so that the entire superficial bed of vegetable 

 mould passes through their bodies in the course of every 

 few years; and in most parts of the forests and pasture-lands 

 of Southern Brazil, where several species of earth-worms 

 abound, the whole soil to a depth of a quarter of a metre 



