SECTION TWO 



12. Wash in distilled water. 



13. Fix in 5% sodium thiosulphate (solution H) for about five 

 minutes. 



14. Wash in tap water. 



15. Dehydrate and mount as usual. 



Technique II — Staining Sections 



1. Fix in the same fixative as used for in toto staining. 



2. Dehydrate in graded alcohols as usual. 



3. Clear in xylol and embed in paraffin wax. 



4. Cut sections at lOjU. and attach them to slides with glycerin 

 albumen or Haupt's fixative. 



5. Dewax and carry through the usual graded alcohols to water. 



6. Immerse in 20% copper sulphate for 48 hours at 37° C. 



7. Rinse briefly in distilled water; then immerse in solution J 

 for twenty-four hours at 37° C. 



8. Reduce in Bodian's developer (solution K) for three to five 

 minutes. 



9. Wash in distilled water. 



ID. Tone in 0-5% gold chloride (solution F) for two to four 

 minutes until the sections become grey. 



11. Wash in distilled water. 



12. Reduce in 2% oxalic acid (solution L) for two to five 

 minutes, controlling by microscopic examination, until the desired 

 degree of staining is achieved. 



13. Rinse in distilled water. 



14. Fix in 5% sodium thiosulphate (solution H) for two 

 minutes. 



15. Wash well in tap water. 



16. Dehydrate through graded alcohols as usual, 



17. Clear in xylol. 



18. Mount in Clearmount, D.P.X., or Emexel, or Canada 

 balsam in xylol. 



Notes: 



(a) The author claimed that the technique gave simple and 

 uniform results, whereas, investigators who were studying regen- 

 eration in planarians up to the time his paper was accepted for 



419 



