196 METHYLEN BLUE. 



The effect is practically identical (except as regards the colour) 

 with that of a negative impregnation with silver nitrate. 



8. MAYER (Zeit. wiss. Mik., vi, 1889, p. 422) stains tissues for 

 about ten minutes in a 1 : 300 or 400 solution of methylen blue in 

 0-5 per cent, salt solution, rinses in salt solution, and puts up in the 

 glycerin-picrate of ammonia mixture given 343. The images are 

 generally positive after injection of the colour into the vascular 

 system ; negative after immersion of the tissues. 



TIMOFEJEW (Anat. Anz., xxxv, 1909, p. 296) impregnates for 

 fifteen to twenty minutes in a solution of 1 : 300 or 400 strength, 

 fixes with a very weak solution of ammonium picrate in salt solution, 

 and puts up in a mixture of 50 c.c. glycerin, 50 c.c. water, and 

 35 c.c. saturated solution of the picrate : or fixes with ammonium 

 molybdate of 8 per cent, and mounts in balsam. 



346. Toluidin Blue or Thionin as succedanea of methvlen blue. 



*/ 



HARRIS (Philidelphia Med. Journ., May 14th, 1898) has found that 

 there is no reaction of methylen blue that cannot be equally well 

 obtained with toluidin blue or thionin. For staining pieces of 

 tissue he takes : 



Toluidin blue, 0-1 per cent. sol. in physio- 

 logical salt solution . . . . .2 parts. 



Ammonium chloride 0-25 per cent, in water . 1 part. 

 Egg albumen . . . . . . 1 ,, 



For injections he uses 1 part of the dye to 1000 of physiological salt 

 solution. 



Any of the methylen blue fixing methods may be employed and 

 the whole technique is the same. 



L. MARTINOTTI (Zeit. wiss. Mik., xxvii, 1910, p. 24) recommends 

 a polychrome toluidin blue, made by adding 0-5 per cent, of lithium 

 carbonate to a 1 per cent, solution of the dye and keeping till a 

 purple-red tone appears. Or, a stock solution made of 1 grm. 

 toluidin blue. 0-5 grm. lithium carbonate, glycerin 20 grms., alcohol 

 5 grms., and water 75. 



