Microtome Sectioning of Material in Paraffin 57 



known adhesives are given here. Albusol is the trade name of a 

 stable, licjuid albumen used in one formula. Sheet gelatin of good 

 grade is used in the last two formulas. 



Adhesive I 



Albusol 5 cc. 



Water 185 cc. 



Formalin (40%) 10 cc. 



Adhesive II 



Gelatin I g. dissolved at 35°C. 



Water 90 cc. 



Formalin (40%) 10 cc. 



Adhesive Ml 



Solution A 



Gelatin 1 g. 



Sodium benzoate 0.5 g. 



Water 100 cc. 



Solution B 



Chrome alum 1 g. 



Water 90 cc. 



Formalin (40%) 10 cc. 



Formula I is usually used full strength. Filler enough of the 

 stock solution to fill a small dropper bottle. The adhesive property 

 becomes weakened in about 1 month. Formula II is used full strength 

 for materials that do not adhere easily. It may be diluted with 2 to 

 5 volumes of water for soft materials that adhere readily. Filter the 

 solution into dropper bottles. Fresh adhesive should be made about 

 every month. Formula III is especially usefid for materials that are 

 difficult to affix to the slide. The two separate ingredients of the 

 formula are stable. Mix 1 volume of A and 6 to 15 volumes of B 

 and filter into a dropper bottle. The mixture keeps for months in 

 a refrigerator. The three adhesives given above are used in the same* 

 manner. 



Decide on the number of pieces to be put on a slide and the 

 size of the cover glass to be used (Fig. 6.6) . Put enough of the 

 adhesive on the slide to float freely the desired amovnit of ribbon. 

 Warm the slide over an alcohol lamp having a wire screen chimney, 

 or on a warming plate, until the paraffin expands, undergoes a change 

 of luster, flattens out, and approaches but does not reach the melting 

 point. Keep the ribbon floating while heating to permit expansion. 

 If the paraffin melts, cellular arrangement and cell details are dis- 

 torted. An insufficiently heated ribbon does not expand or lie flat 

 on the slide and, therefore, does not adhere well. Tough, woody, or 

 elastic subjects are especially difficult to flatten and to attach firmly. 

 If the heated ribbon is cm ved, straighten while still warm by pulling 



