520 PLINY'S NATURAL HISTOKY. [Book XXXI. 



and not only this, but they have a coat of blood 4 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. 5 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, 6 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 tents. 7 

 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 

 defiuxions 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 



4 See B. ix. c. 69. He probably alludes to the semifluid thin coat of 

 animal jelly which covers the sponge in its recent state, and is susceptible 

 of a slight contraction on being touched. 



5 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. 



7 " Penicilli." 



