102 Modern Microscopy. 



s 



foraminifera on a slide, and dry them in the same way as 

 directed for diatoms and polycystina. Moisten the gummed 

 cell with your breath, take up a small quantity of the 

 dried foraminifera on the point of a penknife and place 

 them in the cell. Shake out those that do not adhere to 

 the gum, and put the slide away to dry. Then apply a 

 coat of Miller's cement to the upper edge of the cell, and 

 allow it to become nearly dry. Apply a cover-glass and 

 press it down until it adheres to the cell all round ; put 

 away until quite dry, and then finish off with zinc cement 

 or asphalt. 



LESSON No. 18. 

 DRY MOUNTS. 



Opaque Cells. Place a slide in a turn-table, and run a 

 disc of black varnish on its centre ; allow this to dry. 

 Take a piece of black paper and punch out a disc of the 

 same size as the one on the slide, and gum it on to the 

 varnish spot. Take a cell, either metal or vulcanite, of 

 the required depth and fasten it to the paper disc with 

 gold size, asphalt or any other cement, and put the 

 slide away until quite dry. Now place a very small 

 quantity of gum on the centre of the paper disc, and put 

 the specimen into it ; but take care that the gum does not 

 extend beyond the object, or the appearance of the mount 

 will be spoiled. When the gum has dried, put the slide 

 into the turn-table again, and run a ring of any good 

 cement on the upper surface of the cell, and when this has 

 become about half dry apply a cover-glass, which must be 

 pressed down with a needle point until it adheres firmly to 

 the cement all round the cell. Put the slide aside for an 

 hour or two, and then run on a good coat of asphalt or 

 zinc cement. 



Transparent Cells. Take a cell of the desired depth 

 and apply a coat of cement to one side of it, and allow it 

 to become very nearly dry. Take a slide and warm it 



