Cleaning and Mounting Diatoms, etc. 99 



Hairs. Soak for a day or two in turpentine, and mount 

 in Canada balsam. 



Horns, Hoofs, and Whalebone must be soaked in 

 liq. potassse until soft ; then wash away the potash and 

 place in methylated spirit. Make longitudinal and trans- 

 verse sections in the usual way ; dehydrate, clear in clove 

 oil, and mount in Canada balsam. 



LESSON 12. 



CLEANING AND MOUNTING DIATOMS, 

 POLYCYSTINA, AND FORAMINIFERA. 



To Clean Diatoms Growing upon Algae or Shells. 



Place the algae or shells in a basin, cover them with water, 

 add hydrochloric acid, and stir until effervescence results ; 

 add more acid little by little, until effervescence ceases, 

 stirring from time to time. Now strain through net of 

 sufficiently fine texture to allow the diatoms to pass, but to 

 retain the debris. Allow the strained fluid to settle down, 

 pour off the acid water, and place the deposit in a large 

 test-tube. Add pure hydrochloric acid and boil for twenty 

 minutes ; add some pure nitric acid and boil again for 

 twenty minutes, and while boiling add some crystals of 

 chlorate of potash until complete bleaching results. 

 Eemove all trace of acid or alkali by washing in water, 

 and examine the forms under the microscope. If clean, 

 bottle them up in distilled water for future mounting. If, 

 as is sometimes the case, there has been animal matter 

 present which has not been removed, boil in pure sulphuric 

 acid for a few minutes. Wash away all trace of acid before 

 bottling the diatoms in distilled water. 



To Clean Fossil Diatomaceous Deposits. Break the 

 deposit up into small pieces and place them in a large test- 

 tube, in a moderately strong solution of bicarbonate of 

 soda, and boil gently for two hours, the disintegrated 

 portions being from time to time poured off into a beaker 

 and the boiling in soda continued until all the deposit has 



