372 EMBRYOLOGY 



haematoxylin, fuchsin and anilin blue, while the safranin gentian 

 violet and orange stain as used by de Winiwarter, is a classic 

 method for studying the behaviour of the individual cells in 

 developing organs. A more intensive attack on the cytological 

 asjDcct can be made with the special methods described in the 

 cytology sections (§§ 679, 738). 



811.* Heidenhain's Azan Stain. This stain is good for gonads, 

 and general histological methods. It resembles safranin some- 

 what, but gives a good cytological result, plus a fine histological 

 demonstration of the various elements. Make a 2 per cent, 

 solution of azocarmin in distilled water. Acidify strongly with 

 glacial acetic acid (10 to 15 drops in a small slide staining jar). 

 Stain sections in slide for one hour at 55° C. Rinse in water 

 and differentiate in anilin alcohol (96 per cent, alcohol 100 c.c, 

 anilin oil 0-1 c.c.) ; if differentiation is too slow, add 1 or 2 

 drops of anilin oil to the made-up solution till the correct strength 

 is ascertained. Differentiate till cytoplasm is pale pink, and 

 nuclei red and clear. Examine from time to time, first trans- 

 ferring slide to acid alcohol (96 per cent, alcohol, plus a few drops 

 of acetic acid). Rinse in 96 per cent., plus a few drops glacial 

 acetic. Transfer to 5 per cent, phosphotungstic acid until con- 

 nective tissue is completely decolourised (about two hours). Rinse 

 quickly in water and transfer to : — 



Anilin blue (water sol. Griibler, etc.) . 0-5 grm. 

 Orange G . . . . . .2 grm. 



Acetic acid . . . . . 8 c.c. 



Distilled water ..... 100 c.c. 



Dilute with from one to two times its bulk distilled water. 



Stain one-half to three hours, examining from time to time 

 under microscope. Wash in water, dehydrate in absolute alcohol, 

 xylol, balsam. 



812. Pasini's Method. Fix in alcohol, formalin, sublimate 

 Zenker, etc. Prepare sections and stain in Erhlich or Delafield 

 to show nuclei, differentiating well. Place sections from water 

 into 2 per cent, phosphotungstic acid for ten minutes. Wash 

 quickly in aq. dest., and stain for from fifteen to twenty minutes 

 in the following mixture. Water-blue-orcein (Unna) 30 c.c, 

 2 per cent. Eosin B.A. (Griibler) in 50 per cent, alcohol, 30 c.c, 

 saturated aqueous solution of saurefuchsin 4 c.c, neutral glycerin 

 15 c.c. 



(The Unna's stain is made up as follows : (A) Wasserblau 

 1 grm. in 100 c.c. aq. dest., (B) orcein 1 grm. in 50 c.c absolute 

 alcohol, plus 5 c.c. acetic acid and 20 c.c glycerin. Mix A 

 and B.) 



After staining in the water-blue-orcein acid fuchsin mixture, 



* Refer to glands, §§ 889 to 909. 



