Cleaning aud Mounting Diatoms, etc. 101 



cover-glass. The fall of the drop causes the forms to 

 spread evenly over the cover. It should then be dried 

 slowly over a spirit-lamp. When dry, a small drop of 

 Canada balsam is to be applied and the slide put away out 

 of reach of dust to dry for twelve hours. Now place on a 

 hot plate, and apply gentle heat from a spirit-lamp for 

 about ten minutes. Allow it to cool. Now take the cover 

 up with a pair of forceps, and bring its balsamed surface in 

 contact with the centre of a warmed slide. The balsam 

 should then run to a neat bevelled edge all round the 

 cover ; if it does not, warm the slide a little more until 

 it does. 



Unselected Polycystina. Take the forms from the 

 bottle with a glass tube, and spread them on a slide; dry 

 them over a spirit-lamp. Now clean a cover-glass, fasten 

 it to a slip with your breath, and place a drop or two of 

 balsam on it ; take up some of the polycystina on the 

 point of a knife. and place them in the balsam; stir them 

 well up with a needle and put away for twelve hours. 

 Now bake over a spirit-lamp for ten minutes, and while 

 warm stir up again gently with a needle, and spread the 

 forms evenly over the cover. Warm a glass slide, and 

 proceed as directed for unselected diatoms. 



Selected Diatoms and Polycystina. Take an ounce 

 of distilled water, add 6 or 8 drops of ordinary gum water, 

 and filter. Clean a cover-glass and place a drop of the 

 diluted gum upon it ; put away to dry. 



Spread the diatoms or polycystina on a slip and dry 

 them over a spirit-lamp. Select the desired forms with a 

 fine brush or bristle, and breathe upon the gummed 

 surface of the cover, and place the forms upon it. When 

 dry, apply a drop of balsam and put away out of reach of 

 dust for twelve hours. Bake and finish as directed for 

 unselected slides. 



Foraminifera are generally mounted dry. Make a 

 shallow cell, either transparent or opaque, and place some 

 dilute gum in it, and put away until dry. Spread the 



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