58 Life and Immortalty. 
of the calciferous glands, it is likely that they primarily 
serve as organs of excretion, and secondarily as an aid to 
digestion. Worms consume many fallen leaves. It is known 
that lime goes on accumulating in leaves until they drop off 
the parent-plant, instead of being re-absorbed into the stem 
or roots, like various other organic and inorganic substances, 
and worms would therefore be liable to become charged with 
this earth, unless there was some special apparatus for its 
excretion, and for this purpose the calciferous glands are ably 
adapted. On the other hand, the carbonate of lime, which 
is excreted by the glands, aids the digestive process under 
ordinary circumstances. Leaves during their decay generate 
an abundance of various kinds of acids, which have been 
grouped together under the term of humus acids. These 
half-decayed leaves, which are swallowed by worms in large 
quantities, would, therefore, after having been moistened and 
triturated in the alimentary canal, be apt to produce such 
acids, and in the case of several worms, whose alimentary 
canals were examined, their contents were plainly shown by 
litmus paper to be decidedly acid. This acidity cannot be 
attributed to the nature of the digestive fluid, for pancreatic 
Juice is alkaline, and so also is the secretion which is poured 
out of the mouths of worms for the preparation of the leaves 
for consumption. With worms not only the contents of the 
intestines, but their ejected matter or the castings are gener- 
ally acid. The digestive fluid of worms resembles in its 
action, as already stated, the pancreatic secretion of the higher 
animals, and in these latter pancreatic digestion is necessarily 
alkaline, and the action will not take place unless some alkali 
be present; and the activity of an alkaline juice is arrested 
by acidification, and hindered by neutralization. Therefore 
is seems probable that innumerable calciferous cells, which 
are emptied from the four posterior glands in the alimentary 
canal, serve to neutralize more or less completely the acids 
generated there by the half-decayed leaves. These cells, as 
has been seen, are instantly dissolved by a small quantity of 
