384 METHODS. 



This stain is useful for cytological work, the study of cell division, etc. The 

 preparations are often improved by counterstaining with orange G. 



6. BEALE'S CARMINE. 



Formula: Best carmine i gm. 



Ammonia v 3 c.c. 



Pure glycerin 96 c.c. 



Distilled water 96 c.c. 



Alcohol, 95 per cent 24 c.c. 



Dissolve in ammonia plus part of the water, add the rest of the water, and 

 allow the solution to stand in an open dish until the ammonia is nearly all driven 

 off. Then add the alcohol and glycerin. For use dilute with an equal part of 

 glycerin. Stain for twenty-four hours in an open dish, which, together with a 

 second open dish containing acetic acid, is placed under a bell- jar; wash the 

 sections thoroughly in water and then in very weak hydrochloric acid (i c.c. to 

 500 c.c. water), and again in water. 



Beale's carmine is especially valuable for the study of the central nervous 

 system and of the placenta. 



7. WEIGERT'S COPPER HEMATOXYLIN. 



Formula I: Copper solution: 



Acetate of copper in saturated aqueous solution. 

 II: Hematoxylin solution: 



Hematoxylin crystals 2 gm. 



95 per cent alcohol 20 c.c. 



Distilled water 80 c.c. 



(If the stain does not work, add 0.5 grm. of lithium bicarbonate.) 

 Ill: Iron solution: 



Ferricyanide of potassium 25 gm. 



Borax 20 gm. 



Water 2000 c.c. 



This stain is indispensable for the study of the nervous system after the 

 medullary sheaths have begun to develop; the specimens must be preserved in 

 Miiller's fluid. The method is also valuable for the study of the placenta and 

 uterus. 



1. Place the sections in water. 



2. Place the sections in the copper solution for twenty-four hours. 



3. Wash quickly in water. 



4. Put them in the hematoxylin solution for five to ten minutes. The sec- 

 tions should turn a deep blue-black. 



5. Wash thoroughly in water. 



6. Decolorize in the iron solution; the section must be gently moved about 

 to secure an even decolorization. When part of the section shows a brown color, 

 it should be removed and examined. 



