BRANDT'S GLYCERIN JELLY. 205 



water, pours off the superfluous water, and heats the soaked 

 gelatin until melted. To each fluid ounce of the gelatin^ 

 whilst it is fluid but cool, he adds a fluid drachm of the white 

 of an egg. He then boils this until the albumen coagulates 

 and the gelatin is quite clear, when it is to be filtered through 

 fine flannel, and to each ounce of the clarified solution adds 

 6 drachms of a mixture composed of 1 part of glycerin to two 

 parts of camphor water." 



388. Beale's Glycerin Jelly (How to Work, fyc., p. 57). 

 Gelatin or isinglass, soaked, melted, and clarified if desired, 

 as in the last formula. To the clear solution add an equal 

 bulk of strong glycerin. 



389. Brandt's Glycerin Jelly (Zeit. f. Mik., ii, 1880, p. 69; 

 Journ. Roy. Hie. Soc., iii, 1880, p. 502). Melted gelatin 1 

 part, glycerin 1J parts. 



The gelatin to be soaked in water and melted in the usual 

 way. After incorporating the glycerin, the mixture is to be 

 filtered. This is a point of vital importance, as the gelatin of 

 commerce is always mixed with particles of dust and minute 

 threads. Swedish filtering paper does not allow the fluid to 

 pass through sufficiently, and flannel produces more threads 

 than before. The following simple apparatus is found effec- 

 tive. A wide-necked bottle is broken in two, and the upper 

 part taken. The neck is stopped with a cork having two holes 

 bored in it. In the first hole a glass tube, about 20 cc. long, 

 is inserted so as to project a little into the inside of the bottle, 

 and on the outside it is bent sharply to one side and drawn 

 out into a point of about 1 to 2 mm. diameter. In the 

 second hole a funnel-shaped filter is inserted so that the coni- 

 cal part is inside the bottle and the tube projects a few centi- 

 metres beyond the cork and the neck of the bottle. The 

 apparatus is then placed so that the wide opening of the 

 bottle and of the funnel is uppermost, and some spun glass 

 is pressed into the lower conical part of the filter. In using 

 the apparatus the funnel is filled with glycerin gelatin, and 

 the bottle with hot water, which runs off slowly through the 

 tube in the first hole and is constantly replenished. 



Some drops of carbolic acid should be added to the fluid 

 product of the filtering. For mounting, use warm, by melt- 

 ing a small portion on the slide, the object having been 



