SMALL UTENSILS 



101 



furnished they are free from neither. The best method to cleanse 

 them which will also remove any soluble alkalies adhering to the 



FIG. 46 



Stewart's cover-glass forceps. 

 FIG. 47 



FIG. 48 



Cornet's cover-glass forceps. 



glass, fresh from the factory, is the following: Immerse cover- 

 glasses and slides first in water acidulated with a mineral acid (HC1, 

 HNO 3 , H 2 SO 4 ) ; wash well in ordinary tap 

 water to remove every trace of acid, then 

 wash in alcohol, and wipe dry with a 

 soft clean rag or with Japanese tissue 

 paper. 



Forceps. In order to prepare properly 

 a stained cover-glass specimen it is neces- 

 sary to hold it in a pair of small forceps. 

 Those used most frequently for work of 

 this kind are the Cornet or Stewart forceps 

 or some of their modifications. 



Platinum Rod. The most important in- 

 strument of the bacteriologist is the plati- 

 num rod. It consists of a slender glass 

 rod about eight to ten inches long, into 

 one end of which has been fused a piece 

 of platinum wire about twelve to fourteen 

 inches long. For ordinary work the plati- 

 num wire is rather thin (No. 26 or No. 27); 

 for special work it is well to have* also a 

 strong platinum wire which can^j easily 

 perforate a tissue. The wire of the plati- 

 num rod is either used straight as a needle: ^ Platinum needle c and . IO P- 



.., , , * i mi For most purposes finer wire is 



or with a round loop on its free end. The used, 

 latter arrangement is termed the plati- 

 num loop and is generally used in cover-glass preparations from 

 pus, other fluids, or pure cultures. 



