SARCODINA 



1057 



of a saturated solution of bichlorid of mercury in normal salt 

 solution and one part of absolute alcohol. The mercuric solution 

 is prepared by adding to boiling normal salt solution a little more 

 mercury than will dissolve; on cooling, some of the bichlorid 

 crystallizes out. At no stage of the process must the preparation 

 become dry or the smear is worthless. 



1. Fix in hot (60 C.) Schaudinn's fluid, five to ten minutes. 



2. Harden in 70 per cent alcohol ten to thirty minutes, then wash 

 in 70 per cent alcohol to which a few drops of tincture of iodin 

 have been added until it is distinctly colored ten minutes; store 

 in 70 or 80 per cent alcohol until ready to stain. 



FIG. 122. ENTAMCBBA HISTOLYTICA. Motile forms showing ingested blood cells 

 and clear rectoplasm. (Army Medical School Collection, Washington, D. C.) 



3. The Rosenbusch hematoxylin is quite satisfactory. Transfer 

 the slides to distilled water and change several times until they 

 are free from alcohol, then immerse in 3.5 per cent iron-alum solution 

 for from half an hour to overnight. 



4. Stain in the following solution, after rapid washing in distilled 

 water : 



(a) 1 per cent hematoxylin in 95 per cent alcohol. 



(6) Saturated aqueous solution of lithium carbonate. 



Solution (&) is added to solution (a) until the mixture is a cherry 

 red, four or five drops of lithium to 10 c.c.-of hematoxylin is sufficient. 



The solution is either pipetted onto the slides or they are im- 

 mersed in it. Stain from twenty minutes to overnight. 



5. Wash thoroughly in distilled water. 



6. Differentiate with a weak iron-alum solution (three parts of 



