Earth-Worms in History. 53 
on different occasions, and especially the fact that a worm 
when in any way occupied, no matter what set of muscles 
and ganglia may be brought into play, is often regardless of 
light, are antagonistic to the view of the sudden withdrawal 
being a simple reflex action. With the higher animals, when 
close attention to some object leads to the disregard of the 
impressions which other objects must be producing upon 
them, we ascribe this to their attention being then absorbed, 
and attention necessarily implies the presence of mind. 
Although worms cannot be said to possess the power of 
vision, yet their sensitiveness to light enables them to dis- 
criminate between day and night, and thus they escape the 
attacks of the many diurnal animals that would prey upon 
them. They are less sensitive to a moderate radiant heat 
than to a bright light, as repeated experiments have con- 
clusively shown; and their disinclination to leave their 
burrows during a frost proves that they are sensitive to a 
low temperature. 
Investigation fails to locate in worms any organ of hear- 
ing, from which must be concluded that they are insensible 
to sounds. The shrill notes of a metallic whistle sounded 
near them, and the deepest and loudest tones of a bassoon, 
failed to awaken the least notice. Although indifferent to 
modulations in the air, audible to human ears, yet they are 
extremely sensitive to vibrations in any solid object. Even 
the light and delicate tread of a robin affrights and sends 
them deep into their burrows. It has been said that if the 
ground is beaten, or otherwise made to tremble, that worms 
believe they are pursued by a mole and leave their burrows, 
but this does not stand the test of experiment, for the writer 
has frequently beaten the ground in many places where these 
creatures abounded, but not one emerged. A worm’s entire 
body is sensitive to contact, the slightest puff of air from the 
mouth causing an instant retreat. 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 
