SECTION THREE 



CARBOWAX 400 



This is an organic solvent recommended by Zugibe, Fink & 

 Brown (1959) for oil red O and Sudan 4 for staining carbowax- 

 embedded and frozen sections. 



The authors state that Carbowax 400 fulfils all the requirements 

 of an efficient solvent for lipid staining postulated by Chiffelle & 

 Putt (195 1 ), and has, in addition, several other advantages making 

 it more practical than propylene or ethylene glycol. These 

 advantages are (i) Carbowax (or Waterwax) sections are stained 

 three times as fast; (ii) frozen sections are stained five times as 

 fast; (iii) the staining solution is more rapidly prepared; and 

 (iv) the intensity of staining is greater. 



CEDARWOOD OILS 



Cedarwood oil for clearing is the refined natural cedarwood oil 

 which is employed for clearing pieces of tissue prior to infiltration 

 with, and embedding in, paraffin wax. It is a thin oil, of variable 

 refractive index depending on the source and the particular 

 batch: the average refractive index of the oil being i '510. Cedar- 

 wood oil for clearing is unsuitable for use with oil immersion 

 lenses, and the latter type of oil would be quite unsuitable for 

 clearing tissues. 



CELLOSOLVE 

 (Ethylene glycol monethyl ether) 

 For dehydrating thin slices of tissue and sections 



This reagent is a colourless, inflammable liquid, miscible with 

 water, alcohol, xylol, cedarwood oil, clove oil, and various other 

 oils and solvents. It is a good solvent for many stains, and is 

 coming into increasing use both for animal and plant histology, 

 in place of ethyl alcohol. Many biologists employ cellosolve in 

 preference to the ethyl alcohol for dehydration. However, al- 

 though some workers believe cellosolve to be superior to all other 

 dehydrating agents as it obviates hardening and distortion of 



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