SECTION TWO 



D. Silver nitrate 5% aqueous. 



E. Fontana stain (silver oxide solution) 



F. Aniline oil . . . . . . . . i volume 



Xylol . . . . . . . . I volume 



Technique: 



1. Frozen sections not thicker than lo/^ are fixed in 10% for- 

 malin and afterwards washed in three changes of water for fifteen 

 minutes in each. 



2. Immerse in Solution A at 60° C. for fifteen minutes, in an 

 oven. 



3 . Rinse well in three changes of distilled water. 



4. Immerse in the potassium permanganate for three or four 

 minutes. 



5. Rinse with distilled water for about ten or twenty seconds. 



6. Decolorize with the oxalic acid solution until the brown 

 colour just disappears ; then wash well in distilled water. 



7. Immerse in silver nitrate solution in the dark for an hour. 



8. Wash well with two changes of distilled water in the dark. 



9. Immerse in Fontana's stain for fifteen minutes at 60° C. in 

 the dark. 



10. Wash rapidly in three changes of distilled water. 



11. Immerse in 30% formalin for two or three minutes at 

 60° C. 



12. Wash thoroughly in running tap water; then transfer to 

 slides. 



13. Blot away excess water. 



14. Dehydrate with two changes of absolute alcohol. 



15. Clear in the aniline-xylol (Solution F, above). 



16. Wash with xylol; mount in dammar xylo 



Results: . 



Reticulum is stained black, while collagen is brown. 



N.B. : Sections must be handled with glass needles throughout 

 this technique, as contact with metal instruments will ruin the 

 preparations. 



I 103 



