64 Life and Immortality. 
their base or footstalk. Leaves of other plants, and also 
the petioles of some compound plants, as well as triangular 
bits of paper, dry and damp, were experimented with, and 
the manner of seizing the objects and bearing them into 
their burrows were as amusing as they were novel and 
interesting. The leaves and stems used were such as 
the worms had not been accustomed to in their respective 
haunts. 
When the several cases experimented on are considered, 
one can hardly escape from the conclusion that some degree 
of intelligence is shown by worms in plugging up their bur- 
rows. Each particular object is seized in too uniform a 
manner, and from causes which we can generally under- 
stand, for the result to be attributed to mere chance. That 
every object has not been drawn in by its pointed end may 
be accounted for by labor having been saved by some being 
carried in by their broader ends. There is no doubt that 
worms are governed by instinct in plugging up their bur- 
rows, and it might be expected that they would have been 
taught in every particular instance how to act independently 
of intelligence. It is very difficult to judge when intelli- 
gence comes into play. The actions of animals, appearing 
due to intelligence, may be performed through inherited 
habit without any intelligence, although aboriginally acquired, 
or the habit may be acquired through the preservation and 
inheritance of some other action, and in the latter case the 
new habit will have been acquired independently of intelli- 
gence throughout the entire course of its development. 
There is no &@ grzort improbability in worms having acquired 
special instincts through either of these two latter means. 
Nevertheless it is incredible that instincts should have been 
developed in reference to objects, such as the leaves and 
petioles of foreign plants, wholly unknown to the progeni- 
tors of the worms which have acted in the manner just 
described. Nor are their actions so unvarying or inevitable 
as are most true instincts. 
