118 Methods in Plant Histology 



4. Mixtures of absolute alcohol and xylol; 2, 5, 10, 15, 25, 50, 75, and 

 100 per cent xylol, 3 or 4 hours in each grade. Change the pure 

 xylol once or twice. 



5. Paraffin and xylol, 48 hours. 



6. Melted paraffin in the bath, 30 to 40 minutes. 



7. Imbed. 



8. Section; about 10 /z is a good thickness. 



9. Fasten to the slide. 



10. Dissolve off the paraffin in xylol. 



11. Xylol and absolute alcohol, equal parts, 5 minutes; 100, 95, 85, and 

 70 per cent alcohol, 5 minutes each. 



12. Stain in safranin (alcoholic), 6 hours or over night. 



13. Rinse in 50 per cent alcohol, using a trace of HC1 if necessary; then 

 in 70, 85, 95, and 100 per cent alcohol, 5 minutes each. 



14. Stain in gentian-violet dissolved in clove oil (or in clove oil with a 

 little absolute alcohol), 10 minutes. 



15. Treat with pure clove oil until the gentian- violet stain is satisfactory. 



16. Rinse in xylol, 1 minute. 



17. Mount in balsam. 



18. Label. 



That the paraffin method is tedious and complicated is uni- 

 versally recognized. Many substitutes have been tried, but without 

 enough success to justify even a reference. 



