394 



STAINING MICROSCOPIC OBJECTS 



[Ch. XI 



§ 639. Staining with hematoxylin. — Take a slide of sections pre- 

 pared by the paraffin or the collodion method from the jar of alcohol 

 and plunge it into a vessel of water to remove the alcohol. For stain- 

 ing put the slide of sections into a jar or shell vial of the hematoxylin 

 solution or one can lay the slide flat on the staining rack or some other 

 support and add the stain to the sections (fig. 235-236). It usually 

 takes from 2 to 10 minutes to stain sufficiently with hematoxylin. 



A good plan when 

 one is learning the 

 process is to wash off 

 the stain after one 

 minute, either with 

 a pipette or by put- 

 ting the slide in a 

 dish of water. Wipe 

 off the bottom of the 

 slide and put it un- 

 der the microscope. 

 Light well, use a low 

 power, and one can 

 see the nuclei stained 

 a bluish or purple 

 color, as hematoxy- 

 lin is a nuclear dye. 

 If the color is faint, 

 continue the stain- 

 ing until the nuclei stand out boldly. Sometimes it takes a long 

 time to stain well with hematoxylin. In such a case the jar of stain 

 may be put into the paraffin oven and the heat will accelerate the 

 staining. One may also heat the individual slides as for spreading 

 sections, but one must be careful not to let the stain dry on the 

 sections. As the stain evaporates add fresh stain with a pipette. 



When the sections are well stained with hematoxylin, wash off 

 the hematoxylin with water. If the slide is allowed to stand some 

 time in ordinary water the color is likely to be brighter. This is 

 due to the action of the alkali (ammonia, etc.) usually present in natu- 



Fig. 



235- 



Bowl with Draining Rack and Funnel 

 for Staining Sections. 



