APPENDIX. 



405 



SYNOPSIS OF STANDARD METHODS. 



Assuming that the tissue is of moderate density, has been fixed in Zenker's fluid 

 and preserved in 70 alcohol, with due precautions for the removal of the deposits of 

 mercury (page 390), and that the size of the piece to be cut is approximately a surface 

 of i sq. cm. by .5 cm. thick, the steps in the two standard methods the celloidin and 

 the paraffin are as follows: 



Celloidin. 



1. 95 alcohol, 24 hours. 



2. Absolute alcohol, 24 hours. 



3. Mixture absolute alcohol and ether, 



24 hours. 



4. Thin (C) celloidin, 1-2 days. 



5. Medium (B) celloidin, 1-2 days. 



6. Thick (A) celloidin, 2-4 days. 



7. Mount on fibre-block. 



8. Harden in 80 alcohol, 24 hours. 



9. Cut sections, wet with 80 alcohol. 



10. Stain in Ehrlich's hematoxylin, 5-10 



minutes. 



11. Wash in water, 5-10 minutes. 



12. Acidulated 70 alcohol, about one- 



half minute; wash in water. 



13. Ammoniated water, until again blue. 



14. Wash thoroughly in water. 



15. Stain in eosin, 1-2 minutes. 



16. 70 alcohol, until no color is discharged. 



17. 95 alcohol, 5 minutes. 



18. Clear in carbol-xylol. 



19. Mount in balsam. 



Paraffin. 



1. Stain tissue en masse in borax-car- 



mine, 24-48 hours. 



2. Acid alcohol, 24-48 hours. Delafield's 



hematoxylin may be used (page 

 400 ) instead of borax-carmine. 



3. 70 alcohol, 24 hours. 



4. 95 alcohol, 24 hours. 



5. Absolute alcohol, 24 hours. 



6. Chloroform, 3-6 hours. 



7. Saturated solution of paraffin in 



chloroform, 6-12 hours. 



8. Melted paraffin in oven at 52 C., 2 



hours. 



9. Fresh melted paraffin, 4-6 hours. 



10. Embed in fresh paraffin. 



11. Cut sections, dry. 



12. Expand sections on slide. 



13. Dry slides to attach sections, 12 



hours. 



14. Xylol to remove paraffin, 3 minutes. 



15. Turpentine spirits, 3 minutes. 



16. Mount in balsam. 



If paraffin sections are to be stained on the slide, steps 1-3 are omitted, the tissue 

 embedded and cut and the sections attached to the slides. The paraffin is then re- 

 moved and the tissue prepared for the stain by placing the slides in: 



a. xylol, 3 minutes. 



b. 95 alcohol, 3 minutes. 



c. 80 alcohol, 3 minutes. 



d. 70 alcohol, 3 minutes. 



e. Stain as desired. 



f. Dehydrate in ascending alcohols. 



g. Clear in turpentine. 

 h. Mount in balsam. 



SOME USEFUL SPECIAL METHODS. 



Weigert's Stain for Medullated Nerve-Fibres. This method Is 

 especially adapted to display nerve-fibres invested with medullary substance, 

 the latter appearing dark or slate-blue, while the gray matter and nerve-cells 

 are stained a light yellowish tint. The nervous tissue, in pieces not too 

 large and as fresh as possible, is suspended in a relatively large quantity of 

 Muller's fluid (page 391) for 4-6 weeks, changed daily during the first week 

 and occasionally thereafter. The pieces of spinal cord or brain are then 

 transferred directly, without washing in water, into 70 alcohol, followed by 

 90, and kept in the dark for almost a week, the alcohol being renewed sev- 

 eral times and always when turbid. 



