The Paraffin Method 115 



Smear a few drops of the 1 per cent solution of gum arable on the 

 slide; flood with the bichromate solution; warm to straighten the 

 ribbons; drain off the excess water and let the preparation dry in 

 the light. The exposure to light renders the gum insoluble in water. 

 LePage's glue or Mayer's albumen fixative may be used instead of 

 gum arabic. 



The foregoing directions are taken from Dr. Land's notes. 



REMOVAL OF THE PARAFFIN 



To remove the paraffin, place the slide in a Stender dish of xylol. 

 About 5 minutes will be sufficient for sections 10 ju thick. The time 

 may be shortened a little by gently warming the slide. Never heat 

 the slide enough to melt the paraffin. Never attempt to warm the paraffin 

 over a lamp. Overheating is ruinous. 



Many prefer to remove the paraffin by pouring on xylol or 

 turpentine. Hold the slide at an angle of 45, and pour on a 

 little xylol or turpentine. If the slide has been slightly warmed, 

 this should carry off the paraffin immediately. The reagent used 

 in this first pouring cannot be used again. Now flood the slide 

 several times with the turpentine or xylol, pouring the reagent 

 back into the bottle. 



REMOVAL OF XYLOL OR TURPENTINE 



To remove the xylol, place the slide in equal parts of xylol 

 and absolute alcohol in a Stender dish. After 5 minutes, trans- 

 fer to absolute alcohol, which should also be allowed to act for 

 5 minutes. 



If the pouring process is preferred and turpentine has been used 

 to remove the paraffin, remove the turpentine by flooding the slide 

 with 95 per cent alcohol. About 100 c.c. of turpentine and 200 c.c. 

 of 95 per cent alcohol should be sufficient for fifty slides, even if the 

 sections are to be mounted under the longest covers. By keeping 

 both reagents in bottles and pouring the liquid on the slide, the 

 reagents are always fresh. A given quantity of the reagent will 

 prepare as many slides by one method as by the other. 



