136 METHODS OP MICROSCOPICAL RESEARCH. 



now be dipped in water, and any glycerine that has 

 overflowed or been pressed out, washed off with a 

 camel-hair brush. After drying it can be ringed 

 with shellac varnish followed by white zinc cement. 



Mounting in Glycerine Jelly. 



Specimens to be mounted in glycerine jelly should 

 be immersed in distilled water for some time before, 

 in order to ensure the removal of all alcohol from 

 the tissues, &c. This being done, place a wide- 

 mouthed bottle containing glycerine jelly in a water 

 bath kept warm, but not too hot, by a spirit lamp 

 or a Bunsen's gas burner placed beneath it. Now 

 place the section or other specimen to be mounted 

 precisely in the centre of the slip, and apply the 

 jelly with a small pipette. Then holding a clean 

 cover of the necessary size in forceps, steadily and 

 gently lower it upon the jelly. The cover should 

 touch the slip with its edge furthest from the 

 operator and be gradually lowered so as to drive 

 out air bubbles, if any, and not to disturb the 

 position of the specimen. This is a delicate opera- 

 tion, requiring great care and some practice and 

 experience. The secret of success is do not be 

 sparing of your jelly, apply plenty and you will not 

 be troubled with air bubbles. When cold the excess 

 of jelly can be easily removed with a soft brush, 

 and the slide should be allowed to dry (not rubbed 

 dry) and then ringed with shellac cement and 

 finished with two coats of white zinc cement. 



Mounting in Farrant's Medium. 



The author has constantly been asked how it is 

 that air bubbles are entirely absent from all pre- 



