The Preparation of Whole Mounts and Smears 109 



material is dry, boil it in water containing a wetting agent uniil thor- 

 oughly saturated, jiiniiping with an aspirator it necessary. Divide 

 the material into slivers no thicker than a toothpick. Treat with one 

 oi the following macerating processes. 



Schultze's Metliod.~Co\er the material with concentrated nitric acid. 



Add a few crystals of potassium chlorate. 



Heat gently on a sand bath, in a closed h(K>d, until the material is 

 bleached white. 



Wash thoroughly, and shake with glass l^eads until the material dis- 

 integrates. 



increase or decrease the duration of heating until entire unbroken cells 

 can be isolated. 



Jeffrey's Metliod.— The macerating fluid consists of equal volumes of 10% 

 chromic acid and 10%- nitric acid. 



Treat for 1 to 2 days at 30 to 40°C. 



Wash and shake with glass beads. 



Harlow's Method.— Treat the subdivided and lx)iled material in chlorine 

 water for 2 hr. 



Wash in water. 



Boil in 3% sodium sulphite for 15 min. 



Wash and macerate. 



Repeat chlorination and the sulphite bath if necessary. 



Following any of these maceration treatments, wash the pulp thor- 

 oughly by decantation. A centrifuge is an aid in washing. Unstained 

 material may be mounted in water or glycerin for study. The cells 

 may be lightly stained in aqueous safranin, washed by decantation 

 or centrifuging, and mounted in water. Tlie mounting media de- 

 scribed on page 102 may be used to make semipermanent slides, or 

 the dioxan or butyl alcohol methods can be used to make permanent 

 slides. 



