300 Methods in Plant Histology 



Osmic Acid.- 



Osmic acid 1 c.c. 



Distilled water 100 c.c. 



The bottle in which the solution is to be kept, and also the glass 

 tube in which the acid is sold, must be thoroughly cleaned. Break 

 off the end of the tube, and drop both tube and acid into the distilled 

 water, or simply drop the tube into the bottle and shake the bottle 



until the tube breaks. 



STAINS 



Delafield's Haematoxylin. "To 100 c.c. of a saturated solution 

 of ammonia alum add, drop by drop, a solution of 1 g. of haematoxy- 

 lin dissolved in 6 c.c. of absolute alcohol. Expose to air and light 

 for one week. Filter. Add 25 c.c. of glycerin and 25 c.c. of methyl 

 alcohol. Allow to stand until the color is sufficiently dark. Filter 

 and keep in a tightly stoppered bottle" (Stirling and Lee). 



The solution should stand for at least two months before it is 

 ready for using. 



Erlich's Haematoxylin. - 



Distilled water 50 c.c. 



Absolute alcohol 50 c.c. 



Glycerin 50 c.c. 



Glacial acetic acid 5 c.c. 



Haematoxylin 1 g. 



Alum in excess. 



Keep it in a dark place until the color becomes a deep red. If 

 well stoppered, it will keep indefinitely. 



Boehmer's Haematoxylm.- 



/ Haematoxylin 1 g. 



\ Absolute alcohol 12 c.c. 



B / Alum 1 g. 



\ Distilled water 240 c.c. 



The solution A must ripen for two months. When wanted for 

 use, add about 10 drops of A to 10 c.c. of B. Stain 10 to 20 minutes. 

 Wash in water and proceed as usual. 



Mayer's Haem-Alum. Haematoxylin, 1 g., dissolved with heat 

 in 50 c.c. of 95 per cent alcohol and added to a solution of 50 g. of 



