100 Modem Microscopy. 



broken up. The alkaline solution must then be washed 

 away, and the diatoms boiled for a short time in nitric acid, 

 and when sufficiently clean wash away the acid in repeated 

 changes of water, and bottle up the diatoms in distilled 

 water. 



To Clean Living Diatoms. Eemove all dirt or salt by 

 washing well in water ; shake well, and allow the diatoms 

 to settle before pouring off the water. In this way all 

 soluble impurities can be removed. When the water 

 remains clear pour it off, leaving the diatoms as nearly dry 

 as possible, and cover them with strong alcohol, which will 

 extract the endochrome ; change the alcohol daily until it 

 ceases to be tinged with green ; then wash away the alcohol 

 with water, pour off the water, and place the diatoms in a 

 platinum capsule and heat them to a dull red over a spirit- 

 lamp. This will separate the frustules into single valves, 

 and finish the cleaning of the diatoms, and they may then 

 be bottled up in distilled water. 



To Clean Polycystina. The polycystinous earth should 

 be broken into small pieces and boiled for several hours in 

 a strong solution of common washing soda, the disinte- 

 grated matter being from time to time poured off into a 

 vessel, and the boiling in soda continued until all the earth 

 is broken up. Wash the disintegrated matter in water 

 several times to remove the soda, allow the polycystina to 

 settle down, and pour off the water and place the forms 

 in a test-tube ; add some nitric acid and boil for twenty 

 minutes. Kemove all trace of acid with water and bottle 

 up in distilled water. 



To Clean Foraminifera. All mud must be got rid of 

 by repeated washing in water. Then boil the forms in a 

 strong solution of bicarbonate of soda for an hour or two. 

 When clean, wash away the soda and bottle in distilled 

 water. 



To Mount Diatoms in Canada Balsam (Unselected 

 Slides). The diatoms are to be taken out of the bottle with 

 a dipping-tube, and should be allowed to fall upon a clean 



