174 Animal Micrology 



then in weak hydrochloric acid (1 to 500 of water) and again in 

 water. Minot recommends this stain and method of treatment 

 especially for the placenta and for the central nervous system of 

 embryos. 



36. Carmine, Picric Acid, and Indigo Carmine (Calleja's staining 

 fluid). - 



Solution I. 



Carmine 2 grams 



Lithium carbonate, saturated aqueous solu- 

 tion 100 c.c. 



Solution II. 



Indigo carmine . 0.25 gram 



Picric acid, saturated aqueous solution . 100.00 c.c. 



Place sections in solution I for from 5 to 10 minutes, then 

 into acid alcohol until they become pale red (20 to 30 seconds) ; 

 wash well in water. Next, place the sections in Solution II for 5 

 to 10 minutes, then into acetic acid (0.2 to 0.5 per cent.) for a 

 few seconds and wash well in water. Dehydrate rapidly and 

 clear in xylol. The method is useful for epithelial cells and 

 connective tissue. 



37. Carmine, Acid (Schneider's). Add carmine to boiling 

 acetic acid of 45 per cent, strength until no more will dissolve. 

 Filter the solution when cool. This is a valuable reagent for 

 the study of the nuclei of fresh cells. It is very penetrating and 

 gives a brilliant stain. The strong acetic acid ultimately destroys 

 the cell. 



38. Ehrlich-Biondi Triple Stain (Heidenhain). The ingre- 

 dients should be obtained from Grtibler and Hollborn, Baiersche 

 Strasse 63, Leipzig, or from their agents. 



Acid fuchsin, saturated aqueous solution . . 4 parts 



Orange G " " " . . 7 parts 



Methyl green (Methylgriin OO) saturated 



aqueous solution 8 parts 



The solution of orange should be prepared first, and the solu- 

 tions of fuchsin and methyl green added to it with continual 

 stirring. Each solution must be thoroughly saturated; it takes 



