ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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sections are to be stained. Under (1) an adhesive of the following com- 
position is given: turpentine oil 1, 20 per cent, aqueous solution of 
gelatin 2. This makes an emulsion which may be spread on with the 
lingers. When the sections are placed on this layer they are to be 
pressed down with filter-paper and then allowed to dry in the air. This 
procedure is only intended for sections -which are not large or of such a 
nature that they do not crumple, &c. wlien' 4 treated with the paraffin solvent. 
In such case the section-strips must undergo a previous treatment, and 
this at the stage when they are removed from the ribbon frame just after 
Fig. 24. 
cutting. The one surface must then be covered with a layer of 20 per 
cent, gelatin solution. When dry the strips are placed in 50 per cent, 
spirit and then damp-stretched. By this they are made to adhere to the 
strips, after which, having been dried in air, they are placed in benzin. 
When the sections are to be stained the adhesive recommended is tur- 
pentine oil 1, 2 per cent, aqueous solution of bichromate of potassium 1, 
20 per cent, aqueous solution of gelatin 3. This emulsion must always 
be freshly prepared. When a soft and flexible underlay is requisite, 
then the slides must be coated with a 10 per cent, solution of gutta- 
percha in carbon disulphide, and when the disulphide has volatilized a 
