TECHNIQUE. 51 



tions may be obtained after staining for from 10 to 

 15 minutes. The stained smears are finally washed 

 in running distilled water, the excess of stain removed 

 with alcohol, cleared with xylol, and mounted in acid- 

 free Canada balsam. A good Giemsa stain may be 

 obtained from Grubler and is used in the proportion 

 of 1 drop of the stain to 1 c.c. of distilled water. With 

 this wet-fixed specimens should be stained for from 

 2 to 6 hours, and cleared and mounted as just de- 

 scribed. Fair results are obtained with this stain in 

 air-dried preparations. 



Wright's Method. The following method I have 

 found very satisfactory in staining parasitic amoebae 

 and with it I have been able to follow the entire cycle 

 of development of Entamcpba coli and Entamceba 

 histolytica, as described by Schaudinn. It should be 

 remembered, however, that one has to examine many 

 preparations before this can be accomplished and that 

 the majority of air-dried preparations are almost use- 

 less for the study of minute cytological details. 



The following chemicals are used in preparing 

 Wright's stain: 



1. Methylene blue (Grubler's). 



2. Eosin. Yellow. Water soluble (Grubler's). 



3. Methylic alcohol (Merck's reagent). 



Method of Preparation. The stain is prepared 

 as follows: Add 0.5 gm. of sodium bicarbonate to 

 100 c.c. of distilled water, dissolve thoroughly, and 



