408 sri-:ci.\L Micmworic TECHNIQUE. 



aqueous solution of orange-G for twelve hours. A counterstain 

 in haematoxylin or methylene-blue may be used, giving a prep- 

 aration in which the nuclei are blue, and the red blood-cor- 

 puscles and a-granulations are red. 



^-granulations, basophilic granules (mast cells), are stained 

 violet blue in dahlia (saturated solution in glacial acetic acid, 

 12.5 parts; absolute alcohol, 50 parts; distilled water, 100 

 parts). 



S-granulations are stained in a saturated aqueous methyl- 

 ene-blue solution. The staining requires from five to ten 

 minutes. 



f-granulations, neutrophile cells, are stained best by Ehr- 

 lich's triple stain. This is a saturated aqueous solution of 

 orange-G, 120 parts ; acid fuchsin, 80 parts ; methyl -green, 

 100 parts; to which are added water, 300 parts; absolute 

 alcohol, 80 parts ; and glycerin, 50 parts. This stain is used 

 for from five to ten minutes, and then washed off with water. 

 The red corpuscles are stained yellow, the neutrophile granules 

 violet, the nuclei bluish green, and the eosinophile granules 

 bright red. 



In all these dried specimens the staining fluid is washed 

 off with water and the specimens dried in the air. They are 

 then mounted in balsam. 



34. Blood platelets are obtained by pricking the finger 

 through a drop of 1 per cent, osmic acid. The blood mixes 

 with the acid and is fixed. Instead of osmic acid, one may 

 use methyl-violet (1:10,000) in physiological salt solution, in 

 which the platelets are stained blue. 



7. CIRCULATORY SYSTEM. 



35. Small Blood-vessels and Capillaries. A piece of pia 

 mater from the base of the human brain is washed in distilled 

 water and fixed for from one to two hours in Zenker's fluid. 

 Various stains may be used. 



36. The vascular epithelium in capillaries and small vessels 

 is demonstrated by injecting the vessels of a freshly killed 

 frog with 1.5 per cent, silver nitrate solution. In the 



