the acid contents. The concretions found in the intestines and in
the castings often have a worn appearance, but whether this is due
to some amount of attrition or of chemical corrosion could not be
told. Claparede believes that they are formed for the sake of
acting as mill-stones, and of thus aiding in the trituration of the
food. They may give some aid in this way; but I fully agree with
Perrier that this must be of quite subordinate importance, seeing
that the object is already attained by stones being generally
present in the gizzards and intestines of worms.



CHAPTER II--HABITS OF WORMS--continued.



Manner in which worms seize objects--Their power of suction--The
instinct of plugging up the mouths of their burrows--Stones piled
over the burrows--The advantages thus gained--Intelligence shown by
worms in their manner of plugging up their burrows--Various kinds
of leaves and other objects thus used--Triangles of paper--Summary
of reasons for believing that worms exhibit some intelligence--
Means by which they excavate their burrows, by pushing away the
earth and swallowing it--Earth also swallowed for the nutritious
matter which it contains--Depth to which worms burrow, and the
construction of their burrows--Burrows lined with castings, and in
the upper part with leaves--The lowest part paved with little
stones or seeds--Manner in which the castings are ejected--The
collapse of old burrows--Distribution of worms--Tower-like castings
in Bengal--Gigantic castings on the Nilgiri Mountains--Castings