SPONGES Teh 
Mei OAS TSOP LIVING SPONGES. 
There is no class of animals with which I have had 
any experience which are more difficult to make casts of, 
than Living Sponges. On account of the water which 
they contain, and which cannot be removed from their 
tissues without distroying the sponge, neither plaster nor 
the glue preparation can be used as material for moulds. 
There is, however, fortunately a substance which an- 
swers the purpose admirably. This is wax, and _ paraffine 
wax is what I have used most successfully. 
I place the sponge in a tight box ( pasteboard will do ) 
which is a little large for it, leaving at least half an inch 
around the sponge. The sponge must be fastened to the 
bottom of the box, which can be accomplished by using 
pins or wire, or it will float inthe wax. Melted wax is now 
poured on the sponge until the box is filled, covering the 
sponge about an inch in depth. This wax must not 
be too hot, but still ina sufficiently liquid condition to 
flow into every minute orifice. It must feel very hot to 
the finger, but not hot enough to scald the flesh. 
