50 Life and Immortality. 
the facts already given, that they would have perished in 
their burrows. 
After there has been a heavy rain the film of mud or of 
very fine sand to be seen over gravel-walks in the morning 
is often distinctly marked with the tracks of worms. From 
May to August, inclusive, this has been noticed when the 
months have been wet. Very few dead worms are anywhere 
to be seen on these occasions, although the walks are 
marked with innumerable tracks, five tracks often being 
counted crossing a space of only an inch square, which 
could be traced either to or from the mouths of the burrows 
in the gravel-walks for distances varying from three to 
fifteen yards, but no two tracks being seen to lead to the 
same burrow. It is not likely, from what is known of the 
sense-organs of these animals, that a worm could find its 
way back to its burrow after having once left it. They 
leave their burrows, it would seem, on a voyage of discovery, 
and thus they find new sites for the exercise of their powers. 
For hours together they may often be seen lying almost 
motionless beneath the mouths of their burrows. But let 
the ejected earth or rubbish over their burrows be suddenly 
removed and the end of the worm’s body may be seen 
rapidly retreating. 
This habit of lying near the surface leads to their destruc- 
tion to an immense extent, for, at certain seasons of the year, 
the robins and blackbirds that visit our lawns in the country 
may be observed drawing out of their holes an astonishing 
number of worms, which could not be done unless they lay 
close to the surface. But what brings the worms to the sur- 
face? This is a question whose answer cannot be positively 
asserted. It is not probable that they behave in this manner 
for the purpose of breathing fresh air, for it has been seen 
that they can live a long time under water. That they are 
there for the sake of warmth, especially in the morning, is a 
more reasonable supposition, which seems to be confirmed 
by the fact that they often coat the mouths of their burrows 
