30 



PRACTICAL MICROSCOPY. 



saturated aqueous solution of alum. They must afterward be washed 

 in clean water. 



BORAX-CARMIKE STAIKING PROCESS. 



Arrange your materials as in the diagram, Fig. 16. 



1. Watch-glass two-thirds filled with the carmine fluid. 



3. Saucer containing about an ounce of alcohol. 



3. Salt-cellar filled with a saturated solution of oxalic acid in al- 

 cohol. 



4. Salt-cellar with alcohol. 



5. Porcelain dish containing oil of cloves. 



The carmine solution will stain ordinarily in from three to ten 

 minutes. After the section has been for a few minutes in the dye, 



FIG. 16. DIAGRAM INDICATING THE SUCCESSIVE STEPS IN STAINING WITH BORAX-CARMINE. 



you will lift it with the needle, drain, and transfer to the saucer con- 

 taining alcohol. You^will then be enabled to determine whether the 

 section is sufficiently stained; it should be a deep, opaque red. The 

 alcohol washes off the section, removing the adhering solution of 

 carmine. 



The carmine must now be fixed in the tissue or mordanted; and 

 this you proceed to do by transferring the section to the watch-glass 

 of oxalic acid solution. Notice the change in color, from a dull red 

 to a bright crimson, and when the change is complete, lift it into the 

 salt-cellar containing clean alcohol. This dissolves out the acid, 

 which, if left, would appear later on the specimen in crystals. Five 

 minutes suffice for this washing, after which transfer to the oil of 

 cloves. 



This process does not give as sharp contrasts as the haema. and 

 eosin, but it is simpler and very permanent. It is best to select 

 3ome one process for general work, and adhere to it. The acid of the 

 Carmine process must be guarded with extreme care, as the smallest 

 particle is sufficient to spoil the hsema. solution. Look to it that the 



