STAINING, PRACTICAL AND THEORETICAL 



than eighty new reagents investigated, amylopectin adhesive 

 (solution D, above) proved to be the most successful. This 

 adhesive sticks the sections to glass more firmly than any other 

 medium, but because it breaks down and loses its adhesive 

 properties after eight days, a preservative (Nipa ester No. 8221) 

 is added to prevent this. 



Reference: Steedman, H. F. (1957). 



CELLOIDIN PROTECTION OF ENZYMES, Etc., 

 IN PIECES OF TISSUE AND SECTIONS 



To obviate the loss of water-soluble substances during 



processing 



Solutions required: 



1% and 0-5% Celloidin in equal volumes of 

 ether and absolute alcohol. 



Technique: 



1. Material to be examined for enzymes should be chilled for 

 about twenty minutes in a refrigerator, then cut into slices, not 

 more than 3 mm. in thickness, and fixed in acetone at 0° C. to 

 4° C. for twenty-four hours. 



2. Dehydrate for about twelve hours in each of three changes 

 of absolute acetone. 



3. Immerse in the celloidin solution for twelve to twenty-four 

 hours. 



4. Drain rapidly; then immerse for about forty-five minutes in 

 each of two changes of chloroform. 



5. Embed in paraffin wax at a temperature not exceeding 

 56° C. for a maximum time of one and a half hours. 



6. Cut sections at 3 to 8/x, floating them out on lukewarm 

 water. 



7. Fix sections to slides with albumen. 



8. Place slides on a warm plate or on a box-type microscope 

 lamp to dry the adhesive thoroughly. 



508 



