282 MANIPULATION. 



fluid, or in a fluid of a similar kind ; this should be more par- 

 ticularly attended to when the preparation has to undergo 

 dissection in water previous to its being mounted. It has 

 often happened to the author to find a preparation that had 

 been dissected in water, and mounted in a cell in spirit and 

 water immediately after, completely covered over with small 

 air bubbles in a few hours, from the slow admixture of the two 

 fluids. With Goadby's solution it does not so often happen, 

 but with this a white sediment will be sometimes deposited in 

 the bottom of the cell when the preparation has been soaking 

 in spirit for some time previously. When the operator has 

 more than one specimen of a rare kind, he should not confine 

 himself to mounting them all in one fluid, but should try such 

 others as in his opinion may be likely to succeed ; a note of 

 this should be made at the time on the glass slide, and the date 

 of the mounting also placed thereon ; such records will be of 

 great service as guides to future operations. 



In addition to the fluids employed for the preservation of 

 objects, there are certain agents now coming into use which 

 are solid when cold. The first of these was suggested by Mr. 

 Wenham, and consisted of a mixture of gelatine and treacle ; 

 rthis has since been improved upon by Mr. H. Deane,who, in a 

 paper lately read before the Microscopical Society of London, 

 recommends the following : — Gelatine, 1 oz. ; water, 4 oz. ; 

 honey, 4 oz. ; rectified spirits of wine, g oz. ; creosote, 6 drops. 

 The gelatine is to be soaked in water until soft ; the honey is 

 to be raised to the boiling heat in another vessel and added 

 to the moist gelatine ; the whole is then to be made boiling 

 hot; when it has somewhat cooled, but is still perfectly 

 fluid, the creosote and spirits of wine, previously mixed 

 together, are to be added; the whole is then to be filtered 

 through fine flannel; when cold, the composition is in the 

 form of a very stiff jelly, which, on being slightly warmed, 

 becomes perfectly fluid. A mixture of gelatine and glycerine, 

 as suggested by Mr. De la Hue, will also answer the same 

 purpose. The mode of using these agents will be described in 

 the chapter devoted to the mounting of objects in Canada 

 balsam. 



