64 THE OCEAN. 
and at the end of four weeks the water was found 
to be still pure, the Mollusca and other animals all 
alive and active, the Conferve had grown percep- 
tibly, and the Coralline itself bad thrown out some 
new shoots, and several additional articulations. 
Hight weeks have now elapsed since the experi- 
ment was begun,—the water has remained un- 
changed,—yet the Coralline is growing, and appa- 
rently has lost none of its vitality; but the animals 
have sensibly decreased in number, though many 
of them continue to be active, and show no dis- 
like to their situation. What can be more conclu- 
sive? I need not say that if any animal, or even a 
sponge, had been so confined, the water would long 
before this time have been deprived of its oxygen, 
would have become corrupt and ammoniacal, and 
poisonous to the life of every living thing.”* 
Who is not familiar with Sponge,—with its soft- 
ness, its elasticity, its capacity of absorbing and re- 
taining fluids, and other qualities which render it so 
valuable in domestic economy? And yet how few 
are aware that it is the skeleton of an animal! In 
fact, Sponge is one of those dubious forms which 
God has placed in the great system of Creation, on 
the confines of the two great divisions of organic 
beings, apparently having little in common with 
either. Like the Corallines, the Sponges have af- 
forded occasion for much controvérsy as to their 
proper position; but they are now pretty unani- 
mously assigned to the animal kingdom. The com- 
mon Sponge of household purposes (Spongia offici- 
* British Sponges, p. 215, 
