144 CHAPTER XJi. 



(ibi<L, xviii,- 1880, p. 413). Mayer finds that Partsch's is 

 the more rational, the proportion of alum in it being exactly 

 right, whilst in Czokor's it is insufficient. Partsch's fluid 

 also keeps better. 



RABL (Zeit. wiss. Mik^ xi, 2, 1894, p. 168) takes 25 grins. 

 each of cochineal and alum, 800 c.c. of water, and boils down 

 to 600 c.c. He prefers this because it is not so purely nuclear 

 a stain as the others. 



These solutions give a stain that is practically identical 

 with that of alum-carmine made from carmine, with perhaps 

 even more delicate differentiations. 



BAWITZ (Zeit. wiss. Mile., xxv, 1909, p. 392) takes cochineal 4 grins., 

 nitrate of aluminium (or ammonio-sulphate of cobalt) 4 grins., water 

 100 c.c., and glycerin 100 c.c. Only for sections. 



217. MAYER'S Carmalum (Mitth. Zool. Stat. Neapel, x, 1892, 

 p. 489). Carminic acid, 1 grin.; alum, 10 grms. ; distilled 

 water, 200 c.c. Dissolve with heat (if necessary). Decant 

 or filter. Add some antiseptic, either ] c.c. formol, or O'l 

 per cent, salicylic acid, or 0'5 per cent, salicylate of soda. 

 The solution will then keep. It stains well in lulk, even 

 osmium objects. If washed out with distilled water only, 

 the plasma will remain somewhat stained. If this be not 

 desired, wash out carefully with alum solution, or, in difficult 

 cases with weak acid, followed in either case with water. 

 The general effect is that of an alum carmine stain. 



A weaker solution may be made by taking from three to five times as 

 much alum and five times as much water, and dissolving in the cold. 



With either solution the objects to be stained sliould not 

 have an alkaline reaction. 



RAWITZ (Anat. Anz., xv, 1899, p. 438) takes 2 grms. rarniiinV acid, 20 

 grms. ammonia-alum, 150 c.c. water, and 150 c.c. glycerin. A strongly 

 staining solution, which is said to ke<p well. Only for sections. 



All solutions prepared with alum tend to precipitate. Cannahmi 

 made up with 500 c.c. of water instead of 200, and with glycerin or 10 

 per cent, of formol or pyroligneous acid added, keeps well. 



218. MAYER'S Aqueous Aluminium-Chloiide-Solution (Mitth. 

 Zool. Stat. Neapel, x, 1902, p. 490). Carminic acid, 1 grin. ; chloride 

 of aluminium, 3 grins. ; water, 200 c.c. Add an antiseptic, as for car- 

 maluni. 



