78 HOW TO USE THE MICROSCOPE 



taking two vessels (such as tumblers or jugs) and 

 dissolving 1 ounce of chloride of lime in 10 ounces 

 of water in one, and 2 ounces of washing soda in 

 10 ounces of water in the other. Then the two 

 solutions are mixed and shaken. After standing 

 to settle for a day or so, the clear fluid is filtered 

 and bottled. Sections to be bleached are given a 

 good soaking in water, and then immersed in 

 bleaching fluid for an hour or more. Bleaching 

 may take several hours, but the sections should 

 be carefully watched while undergoing this process. 

 When bleaching is complete, the sections are washed 

 in several changes of water in order that no trace 

 of chlorine or soda may remain about them. 



The worker has a number of stains from which 

 he may choose, but for his first efforts I woidd 

 advise him to avoid all others in favour of haema- 

 toxylin, which is prepared from logwood. It will 

 simplify matters if an aqueous solution of hsema- 

 toxylin be purchased at the dealer's. To stain, fill 

 a watch-glass with distilled water, and add 10 to 

 20 drops of the haematoxylin solution ; soak the 

 section in this stain for a period which may vary 

 from ten minutes to half an hour. When sufficiently 

 stained, wash the section first in distilled water and 

 afterwards in tap water. Dehydrate with two 

 changes of methylated spirit, clear by ten minutes' 

 immersion in clove oil, transfer to turpentine, and 

 mount in balsam and benzole. If the section is 

 too deeply stained, the colour may be reduced by 

 soaking for five or ten minutes in a ^ per cent, solu- 

 tion of acetic acid (glacial) in distilled water. 



Glycerine jelly is an excellent mounting medium 



