430 CHAPTER XXXII. 



ten seconds with a mixture of 1 grm. Saurerubin (Rubin S.), 

 400 c.c. 2 per cent, acetic acid, and 400 c.c. saturated solu- 

 tion of picric acid, or for half an hour in a mixture of 3 to 5 

 c.c. of the above stain with 100 c.c. of 96 per cent, alcohol, 

 and washes out well with alcohol. 



POPOW (Zeit. f. wiss. Mik., xiii, 1896, p. 358) makes up 

 the stain by adding a few drops of tincture of iodine to a 

 1 per cent, solution of Saurerubin (Rubin S.). 



BUECKHAKDT (La Cellule, xii, 1897, p. 364) also finds that 

 Saurerubin gives a better stain than Saurefuchsin, and 

 recommends 1 part of saturated aqueous solution thereof to 

 9 parts of picric acid solution of 1 : 300 strength. Nuclei 

 may be previously stained with methyl violet. 



777. Methylen Blue for Central Nervous System (SEMI MEYEE, 

 Arch. f. mik. Atiat., xlvi, 1895, p. 282, and xlvii, 1896, p. 734). MEYER 

 has obtained good results (for the central nervous system, not for the peri- 

 pheral) by means of subcutaneous injection. Large quantities of solution 

 must be injected. A young rat will require at least 5 c.c. of 1 per cent, 

 solution; a rabbit of a few weeks about 40 c.c. But it is better to employ 

 stronger solutions, 5 to 6 per cent. The total dose should be given in 

 several portions, at intervals of one to several hours. It is not necessary to 

 wait till death by intoxication has taken place, and after a suitable interval 

 the subject maybe killed. It is not necessary to expose the organs to the air 

 for the sake of " oxydising " the stain. The)' should be thrown direct into 

 the bath of BETHE, 329. The liquid ought to be well cooled before use. 

 The preparations should remain in it till the next day. 



RAMON Y CAJAL (Rev. trim. Micr., Madrid, i, 1896, p. 123 ; Zeit. f. iviss. 

 Mik., xiv, 1897, p. 92) stains by " propagation " or " diffusion." The brain is 

 exposed (rabbit) and the cortex is divided into slices of a couple of millimetres 

 thickness by means of a razor. The slices are then covered on both sides 

 either with finely powdered methylen blue, or with a saturated solution of 

 the same, the slices are replaced in their natural positions, the brain-case is 

 replaced for half an hour, after which the slices are removed and fixed for 

 a couple of hours with Bethe's ammonium niolybdate, washed, hardened 

 for three or four hours in a mixture of 1 part 1 per cent, platinum chloride, 

 40 parts formol, and 60 parts water, further treated with platinum chloride 

 of 1 in 300, passed through alcohol, and if small enough imbedded in 

 paraffin. 



778. GIACOMINI'S " Dry " Process for Preserving Brains (Arch, 

 per le Scienze Mediche, 1878, p. 11). See previous editions. 



