1899J MICROSCOPICAL JOURNAL. 39 



brush with the black varnish, turn a disc say three-quar- 

 ters of an inch in diameter. It is best to make a number 

 of these at a time. Place aside to dry for say twenty- 

 four hours at least, before it is fit to use for thispurpose. 

 When dry, take some dull black paper gummed on the 

 white side, cut some discs a little smaller than the black 

 disc on the slip, say about 5-8in. These discs are easily 

 cut out with a gun wad punch, or may be purchased at a 

 very cheap rate ready punched. When the black varnish 

 disc is quite dry, stick one of these in the centre, take a 

 tin cell of a size suitable for the object you are intending 

 to mount, apply a little cement to one side, set aside for 

 ten or fifteen minutes to harden the cement a little. Now 

 with a pair of forceps, place it in position on the black 

 paper, press down and set aside for five or six hours to dry. 

 If a deep cell is required, several thin ones may be fast- 

 ened together to the required height with the cement. 

 The object of the black varnish disc on the glass is to give 

 it a neat appearance on the under side. Take a piece of 

 skin of sole as a sample object, apply a little gum to the 

 black paper, and when it is dry moisten a little with a 

 brush, and place specimen in position (this method will 

 prevent the gum being absorbed by it, causing an unsight- 

 ly mark), be sure all is quite dry before you proceed to 

 put on the cover glass ; having placed the slide under a 

 low power, to see all is clean, take a little cement and 

 place it round the top edge of the cell, put it aside for ten 

 minutes. Have your covers ready cleaned, take one up 

 in the forceps, place one edge on the cement, -and gently 

 lower it down into position. Press down with the needles 

 on the cell and not in the centre of the thin glass. If 

 these directions have been properly carried out, the ad- 

 hesion between the cement and the glass will be perfect, 

 and if the proper quantity has been used, there will be 

 little or no excess. The slide may now be put aside to 

 harden the cement, for an hour or so. It is possible to 



