PRESERVATIVE MEDIA. 221 



appearance in it. The best proportion seems to be one part of 

 Glycerine to two parts of Camphor-water. The following method 

 of using Glycerine, devised by Herr Hantzsch, of Dresden, is said 

 to be peculiarly effective for minute Vegetable preparations : — A 

 mixture is made of 3 parts of pure Alcohol, 2 parts of Distilled 

 Water, and 1 part of Glycerine ; and the object, laid in a cement- 

 cell, is to be covered with a drop of this liquid, and then put 

 aside under a bell-glass. The Alcohol and Water soon evaporate, 

 so that the Glycerine alone is left ; and another drop of the liquid 

 is then to be added, and a second evaporation permitted ; the 

 process being repeated, if necessary, until enough Glycerine is left 

 to fill the cell, which is then to be covered and closed in the usual 

 mode.* The preparation known as Deane's Gelatine is one of the 

 most convenient media for preserving the larger forms of Confervae 

 and other Microscopic Alga?, as well as sections of such as are still 

 more bulky. This is prepared by soaking 1 oz. of Gelatine in 4 oz. 

 of Water until the gelatine is quite soft, and then adding 5 oz. of 

 Honey previously raised to boiling heat in another vessel ; the whole 

 is then to be made boiling hot, and when it has somewhat cooled, 

 but is still perfectly fluid, 6 drops of Creosote and \ oz. of Spirit 

 of Wine, previously mixed together, are to be added, and the 

 whole is to be filtered through fine flannel. This composition, 

 when cold, forms a very stiff jelly ; but it becomes perfectly fluid 

 on the application of a very slight warmth, and may then be used 

 like any other preservative liquid, care being taken, however, that 

 the slide and the glass cover are themselves gently warmed before 

 it comes into contact with them. The purpose which the honey 

 answers in this medium — that of preventing it from becoming too 

 hard — may be as well, or in some cases better, answered by 

 Glycerine ; and the Glycerine Jelly, prepared by the following 

 process {see Lawrance in "Quart. Journ. of Microsc. Science," 

 Vol. vii. 1859, p. 257), may be very strongly recommended as good 

 for a great variety of objects, Animal as well as Vegetable, subject 

 to a caution to be presently given : — "Take any quantity of 

 Nelson's Gelatine, and let it soak for two or three hours in cold 

 water ; pour off the superfluous water, and heat the soaked gela- 

 tine until melted. To each fluid ounce of the Gelatine add one 

 drachm of Alcohol, and mix well ; then add a fluid drachm of the 

 white of an egg. Mix well while the gelatine is fluid, but cool. 

 Now boil until the albumen coagulates, and the gelatine is quite 

 clear. Filter through fine flannel, and to each fluid ounce of the 

 clarified Gelatine add six fluid drachms of Price's pure Glycerine, 

 and mix well. For the six fluid drachms of glycerine a mixture 



* See the Rev. W. W. Spicer's " Handy-Book to the Collection and 

 Preparation of Freshwater and Marine Algas, &c," pp. 57-50. " Nothing," 

 says Mr. Spicer, " can exceed the beauty of the preparations of Desmi- 

 diacce prepared after Herr Hantzsch's method; the form of the plant 

 and the colouring of the endochrome having undergone no change what- 

 ever." 



