148 ON GUTTA-PERCHA AS A PERMANENT STOPPING. 



first, to deprive the gutta-percha of its colouring 

 matter, and secondly, to find some material to mix 

 with it, of a pure white colour, insoluble and un- 

 changeable in the mouth, and capable of being 

 obtained in an impalpable powder, so as to be incor- 

 porated so thoroughly with the gutta-percha as to 

 form one homogeneous mass, giving it more firm- 

 ness and solidity without impairing its tenacity. 



A few years ago, not having met with any of the 

 gutta-percha cements which were unobjectionable 

 in point of colour, consistence, or chemical com- 

 position, I determined to attempt the solution of 

 the problem myself, and commenced a series of ex- 

 periments for the purpose, which were at last 

 crowned with tolerable success. 



To get rid of the colouring matter, a quantity of 

 the native gutta-percha is pulled to pieces repeatedly 

 in hot water, until all dirt and accidental impuri- 

 ties are removed ; it is then dried, and with the aid 

 of heat worked up into httle balls about half an 

 ounce in weight ; one of these balls is tied up 

 tightly in a piece of fine calico, the ends of the 

 ligature being left a few inches long; it is then 

 placed in a wide-mouthed bottle, nearly filled with 

 chloroform, and the ends of the string fixed to 

 opposite sides of the mouth of the bottle by a piece 

 of wet bladder tied tightly over it, the bag of 

 gutta-percha being thus retained close to the top of 

 the bottle, which is then inverted, and set aside for 



