ACID PHOSPHATASE 83 



5. The following morning place in xylol, and let stand until 

 evening. 



6. Transfer to a xylol-paraffin mixture containing just enough 

 xylol to keep the paraffin in soln. at room temperature and let stand 

 overnight. Tissuemat (Fisher Scientific Co.) gives better results than 

 paraffin. In a warm room the variety melting at 60-62° gives better 

 sections than the material having a lower melting point. 



7. Place in a soln. of 1 vol. xylol + 2 vol. melted paraffin in 

 a 60° oven for 1-2 hr. 



8. Infiltrate with melted paraffin for 2 hr, in the oven, then 

 change to fresh paraffin for 4 hr., and finally embed. 



9. Cut sections 10 /x thick and mount on slides with aid of Mayer 

 albumin. (Combine 1 vol. filtered fresh egg white with 1 vol. glyc- 

 erol, and add a bit of camphor as a preservative.) Smear the liquid 

 in a thin film on a slide and rub with the finger, cover with water, 

 transfer section to the slide, place in oven for 5 min. at about 55° to 

 soften the paraffin and allow wrinkles to straighten out, drain off 

 water with a towel, and allow to dry for 2 hr. in the 55° oven. Store 

 mounted sections in refrigerator until ready for use. 



10. Remove paraffin from sections with two changes of xylol fol- 

 lowed by two changes of absolute alcohol. 



11. Dip slides into 0.5-1.0% collodion in alcohol-ether to cover 

 section with a protective film; harden film by dipping into 80% 

 alcohol, and wash with distilled water. 



B. Rootlet and leaf section of the sprout: 



1. Place in the following solns., for 1 hr. in each case, in the order 

 given : 



a. 70% alcohol 



b. 80% alcohol 



c. 65 ml. 80% alcohol -^ 35 ml. n-butyl alcohol 



d. 45 ml. 95% alcohol ~ 55 ml. n-butyl alcohol 



e. 25 ml. absolute alcohol ^ 75 ml. n-butyl alcohol 



f. n-butyl alcohol 



g. xylol 



2. Follow step 6 under A in the preceding part, allowing the 

 material to stand in the mixture for only i/^ hr. 



3. Subject the material to three changes of melted paraffin in the 



