CELLULOSE AND CHITIN 53 



The most recent method for this treatment is that of Murray ( 1937) , 

 but the Diaphanol technique has been widely employed. Once sec- 

 tions are prepared they may be stained by the procedure of Zander, 

 Schulze, or Bethe given in Lee ( 1937, page 600j . 



Murray Method for Softening Chitin 



SPECIAL REAGENTS 



Formalin- Saline Fixative. 10% formalin in 0.8% sodium chloride 

 soln. 



Dehydrating Fixative. Equal vol. absolute alcohol, chloroform, 

 and glacial acetic acid to which mercuric chloride is added to 

 saturation ( about 4% ) . 



Chloral Hydrate-Phenol Reagent. Equal weights of chloral hy- 

 drate and phenol warmed together until they blend to an oily 

 liquid that is fluid at room temperature. 



PROCEDURE 



1. Fix material in the formalin-saline soln. 



2. Transfer to the dehydrating fixative. 



3. Place specimen in the chloral hydrate-phenol reagent for 12- 

 24 hr. or longer. 



4. Clear with xylol, chloroform, or carbon disufide and imbed 

 in paraflfin. 



Diaphanol Method for Softening Chitin 



SPECIAL REAGENTS 



Diaphanol Solution. Pass vapors of chlorine dioxide into ice-cold 

 50% acetic acid. Store in a cool dark place in a glass-stoppered 

 bottle. (Before the war, Diaphanol was sold by Leitz; and Lee — 

 1937, page 598 — recommends buying, rather than preparing, the 

 soln. However, it will probably be impossible to buy for some 

 time, and there is no reason why the reagent cannot be safely 

 prepared if the obvious precautions of working in a hood, etc., 

 are taken.) 



PROCEDURE 



1. Fixed material is rinsed in 63% alcohol and placed in Di- 

 aphanol in a glass-stoppered bottle in diffuse daylight until bleached 



