AND PHYSIOLOGY OF THE SPONGIAD^. 
749 
these bodies, from the circumstance that silk is readily soluble in strong ammonia, satu- 
rated with oxide of copper, whilst sponge is scarcely, or not at all, affected by long 
maceration. My own experiments prove the same fact, yet it is not impossible that the 
minute quantities of iodine, phosphorus, and sulphur present in sponge may modify the 
solubility of the fibre. 
“ Under the supposition that a resinous gum might act as a protection, portions of 
sponge were boiled in benzol, ether, and alcohol, but these solvents did not modify the 
characters in any noticeable degree. 
Flustra 
foliacea. 
Sertularia 
operculaia. 
Spongia 
officinalis. 
Silk from Bombyx, 
Ignited. 
Yields a nitrogenous 
odour. 
Yields a nitrogenous 
odour. 
Yields a nitrogenous 
odour. 
Yields a nitrogenous 
odour. 
Leaves much ash, in 
the form of a fac- 
simile of the frond. 
Chiefly composed of 
carbonate of lime. 
Leaves much ash, but 
much less than the 
preceding. 
Leaves a white ash in 
some quantity. 
Leaves much ash. 
Boiled in water and 
subsequently in 
acetic acid. 
Acid disengages much 
carbonic acid. 
Apparently 
unaffected. 
Apparently 
unaffected. 
Apparently 
unaffected. 
The zoophyte disinte- 
grates and leaves a 
brown flocculent re- 
sidue. 
Form unchanged. 
Form unchanged. 
Form unchanged. 
Washed and boiled in 
concentrated hy- 
drochloric acid. 
Greater part soluble 
in the acid. 
Almost entirely dis- 
solved after ten 
minutes’ boiling. 
Almost entirely dis- 
solved. 
About f soluble in 
the acid. 
A brown gelatinous 
mass remains. 
The residue is gelati- 
nous. 
Gelatinous residue. 
Tannic acid added to 
the hydrochloric 
acid solution. 
A white precipitate, 
insoluble in acetic, 
but soluble in oxa- 
lic acid. 
A white 
precipitate. 
A white 
precipitate. 
A rather copious white 
precipitate. 
Potash added to the 
hydrochloric acid 
solution. 
Ammonia gives simi- 
lar reactions. 
Precipitation of a few 
flocks. 
No precipitate of 
any consequence. 
Small quantityof a ge- 
latinous precipitate. 
A few flocks precipi- 
tated. 
Tannic acid added to 
the above neutral- 
ized solution. 
An abundant yellow- 
ish precipitate. 
If alkali in excess, the 
precipitate is violet. 
Abundant precipitate. 
Abundant precipitate. 
Copious precipitate, 
which takes a flesh 
tint by excess of 
ammonia. 
which turns reddish 
purple by excess of 
alkali. 
Coloured by excess of 
alkali. 
Bichloride of mercury 
added to the hydro- 
chloric solution. 
Slight white 
precipitate. 
Slight precipitate. 
Slight precipitate. 
Precipitate rather 
more copious than 
that from sponge. 
Boiled in a solution of 
oxide of copper in 
ammonia. 
Insoluble. 
^ Insoluble. 
Perfectly soluble ; not 
again precipitated 
by acetic acid. 
5 K 2 
