848 SUMMAEY OF CUKRENT RESEARCHES RELATING TO 



right amount of heat has been applied, the object will be firmly 

 attached, but will not sink into the cement. The slide is then placed 

 on the hot plate, where it remains until the japan is baked perfectly 

 hard, so that no subsequent heating will soften it. 



After the objects are fixed and sufficiently heated, they are allowed 

 to cool, and the ring applied to make the cell. This ring is of tin-foil, 

 made as previously described.* A ring of black cement is carefully 

 applied to the cool slide, and the tin ring pressed into it. Care is 

 taken that none of the cement comes into the cell. This cement is a 

 quick-drying dead colour, used by coach painters, and I think will 

 soon be put on the market in tubes for use in mounting. It is thick, 

 and sets in a few minutes. If necessary, another tin ring is laid on top 

 of the first, in the same cement, and the cell is in this way built up 

 until the cover-glass will be close to the object but not touching it. 

 The cover is then put on with the black cement, clipped and set away. 

 In an hour the clip can come off and anotlier coat of black may be 

 applied. This must dry hard, which requires several hours, when 

 another coat is put on and left to harden. The next day a coat of 

 shellac cement is put on. This should not be too thick, and the mount 

 should be examined carefully to see that no holes are left in the 

 shellac. The next day the white zinc may go on to fill up the angles 

 and make a smooth surface, and in two or three days the final finish 

 may be applied. It will thus be seen that the slide is completely 

 finished in four or five days from the time it is started, that there is no 

 need of having a lot of cells made in advance, but that each one is 

 made to suit the particular object it is to contain, and if proper care be 

 taken the object will be firmly attached to the slide, and there will be 

 no running in. Of course some experience is required to know just 

 when the conditions are fulfilled to ensure complete success, but it 

 may be attained in the use of the means I have just pointed out. 



For fluid mounts in cells I use the tin rings, cementing them to 

 the glass with shellac, which I generally thicken with Chinese 

 vermilion. After the object and fluid are put in the cell, the cover is 

 laid on, the excess of liquid pressed out carefully, and the whole dried 

 with blotting paper. Some of the thickened shellac is then put 

 around the edge of the cover and left to harden. In an hour the 

 slide can go on the turn-table, and a ring of shellac may be applied. 

 No clip should be used. The next day the slide may be carefully 

 washed and dried, when it is ready for another shellac ring. After 

 this is set the white zinc may be put on as usual. Of course the fluids 

 used must not be those that dissolve shellac, but camphor water or 

 glycerin may be used without fear." 



Preparing Cuticles of Plants-f — Mr. F. Kitton gives the follow- 

 ing process for preparing slides of the cuticles of Deutzia, Onosma, 

 Alyssum, Hippopjiae, Equisetum, scalariform and spiral vessels, &c. 

 The apparatus required is only a small porcelain saucer holding 

 about an ounce, a spirit-lamp, a large watch-glass, two or three 

 mounted bristles (rabbit or cat's whisker), about | inch beyond the 



* See this Journal, ante, p. 702. f Sci.-Gossip, 1881, p. 182. 



