520 
pliny's natural histokt. 
[Book XXXL 
and not only tjiis, but they have a coat of blood* even, adhering 
to them. Some say that they regulate their movements by 
the sense of hearing, and that at the slightest noise they con- 
tract themselves, and emit an abundant moisture : when such 
is the case, it is said, it is impossible to tear them away from 
the rocks, and consequently they must be cut, an operation 
during which they emit a sanious secretion. Those sponges, 
too, are preferred to all others, which are grown on spots with 
a north-east aspect, the physicians assuring us that these re- 
tain the breath of life the longest of all ; a circumstance which 
renders them additionally useful to the human body, from the 
union which is thereby effected of their vital principle with 
our own.^ It is for this reason, too, that they are preferred as 
fresh as possible, and in a moist state rather than dry. They 
are not so useful, however, if applied with hot water,^ and 
still less so if they are oiled, or applied to the body when just 
anointed. The compact sponges, it is thought, have less adhe- 
sive power than the others. 
The softest kind of sponge are those employed for tentsJ 
Applied with honied wine, sponges reduce swellings of the eyes, 
and are extremely useful for the removal of rheum from those 
organs, the very finest and softest being of necessity selected 
for the purpose. Sponges are applied, also, with oxycrate, to 
defluxions of the eyes, and, with warm vinegar, for head-ache. 
In addition to these properties, fresh sponges are resolvent, 
emollient, and soothing; but when old, they lose their 
healing properties for wounds. They are employed, also, in 
medicine, for cleansing sores, and for either fomenting or cover- 
ing the parts fomented, till some other application is made. 
Applied topically, they have a healing effect upon running 
ulcers, and upon sores on the bodies of aged persons. Fractures, 
too, and wounds are most effectually fomented with sponge ; 
and when surgical operations are performed, it instantly ab- 
sorbs the blood, so as to allow the incision to be seen. Sponges 
are applied, also, as a bandage, to inflamed wounds, sometimes 
* See B. ix. c. 69. He probably alludes to tlie semifluid thin coat of 
animal jelly which covers the sponge in its recent state, and is susceptible 
of a slight contraction on being touched. 
^ A fanciful notion, certainly. 
6 Hot water renders them greasy, so to say ; an inconvenience which 
may be remedied by steeping them in an alkaline solution, or in urine. 
^ " Penicilli." 
