Microscopical Essays. 155 



The polypes are commonly infefted with little lice ; from thefe 

 iris neceflary to free them, in order to preferve your polypes 

 in a good ftate of health. They may be cleanfed from the lice 

 by rubbing them with a hair pencil 5 this cannot be ealily done, 

 without they have affixed themf Ives to fome fubftanoe : fo that 

 if they are fufpended from the furface of the water, you mud en- 

 deavour to get them to fix themfelves to a piece of packthread ; 

 when they are fattened thereto, you may then rub them with a 

 hair pencil, without loofening them from the thread. 



The lice which torment the polype are not only very 

 numerous, but they are alfo very large relative to it's fize : they 

 may be faid to be nearly as large with refpecl to them, as a com- 

 mon beetle is to us. If they are not rubbed off, they foon cover 

 their bodies, and in a little time totally deftroy them. 



To preferve the polypes in health, it is alfo neceflary often to 

 change the water they are kept in, and particularly after they 

 have done eating ; it is not fufficient to pour the water off, all 

 the polypes mould be taken out, and the bottom and fides of the 

 veffel rubbed from the {limy fediment adhering thereto ; this is 

 caufed by their feces, and is fatal to them if not cleaned 

 away. The fasces often occafion a.fpecies of mortification, which 

 increafes every day ; it's progrefs may be flopped by cutting off 

 the difeafed part. To take them out, firft loofen their tails from 

 the fides or bottom of the glafs ; then take them up one by one, 

 with a quill cut in the fhape of a fcoop, and place them in ano- 

 ther glafs with clean water; if they cling to the quill, let it 

 remain a minute or two in water, and they will foon difengage 

 themfelves. 



• \ U 2 ' They 



