TECHNIQUE. 53 



The staining solution is prepared as follows : Take 

 0.3 gm. of the powdered precipitate and add it to 100 

 c.c. of pure methylic alcohol (Merck's reagent) , filter, 

 and to 80 c.c. of the filtrate add 20 c.c. of the 

 methylic alcohol, or if more than 80 c.c. be left after 

 filtration, enough to bring the entire amount up to 

 100 c.c. The staining solution is now ready for use 

 and will keep unimpaired for weeks. 



To stain, add a few drops of the staining solution 

 to the preparation of feces without preliminary fixa- 

 tion, or previously fixed, while wet, with osmic acid 

 vapor followed by alcohol, and let stand for five 

 minutes; then add enough distilled water to cause a 

 slight metallic scum to form on the surface of the 

 preparation; let stand for from 10 minutes to an hour 

 and wash thoroughly in running distilled water. If 

 stained too deeply, wash in alcohol and xylol. If it is 

 desired to preserve the specimens, mount in Canada 

 balsam. The best results are obtained with wet-fixed 

 preparations, but carefully stained air-dried speci- 

 mens give good results for ordinary work. 



Other methods of staining the amoeba? in the feces, 

 or in the pus from liver abscesses, have been recom- 

 mended, but none of them will be found as satis- 

 factory as those which have been described. 



TECHNIQUE OF STAINING SECTIONS OF TISSUE 

 CONTAINING AMCEB^E. Sections of the infected in- 

 testine or of the walls of liver abscesses are most use- 



