CHAPTER XXVI. 333 



Griibler is much less satisfactory. Nile blue B, Janus green G, 

 methylen blue med., pyronin, Bismarck brown, and methyl violet 

 5 B, will all tinge the mitochondria, but faintly. Cowdry claims 

 that in dilution 1 : 500,000 Janus green is specific, and will not 

 stain granules other than mitochondria : it seems certain at any 

 rate that exceptions to its specificity for mitochondria alone are 

 rare. Cowdry (loc. cit.), in his admirable discussion on the Janus 

 colours (pp. 86 93), states that the specificity of these dyes is due 

 to a diethylsafranin group. Janus black consists partly of Janus 

 green and another substance ; so also Janus blue and grey. See also 

 " Bayliss," 207. For a treatment of the Benzidine dyes, see 790. 



701. Mitochondria of Blood and Cell Smears (COWDRY, Internal. 

 Monat. f. Anat. u. Phys., Bd. xxxi). Janus green B, 1 : 10,000 in 

 0-85 per cent. NaCl. Place a drop on a series of six or more slides : 

 add a small amount of freshly drawn blood (etc.), and then apply 

 coverslip. Do not attempt to mix the cells and the Janus green. 

 The mitochondria stain rapidly, and the preparation, after ringing 

 with vaseline, will last hours. 



702. Injection of Janus Green B (BENSLEY, Amer. Journ. Anat., 

 xiii, 1911). Kill the animal (we believe coal gas seems preferable 

 for this), inject 1 : 10,000 Janus green in salt solution, through 

 left ventricle or aorta by gravity pressure ; in order to obtain a 

 good penetration clamp up the return flow momentarily. After 

 ten minutes' perfusion small pieces of the gland (pancreas in this 

 case) may be removed and examined microscopically for mitochon- 

 dria. When the desired depth of staining has been reached the 

 entire gland is placed in salt solution pending further study. 



703. Neutral Red. Use as above for Janus green ( 700) in 

 1 : 2,000 to 1 : 10,000 solution (see 308, 790, and 804). 



704. Toxic and other Examining Media for Mitochondria of Blood, 

 Protozoa, and Fresh Cells. The mitochondria can be examined 

 successfully in toxic solutions such as weak Os0 4 , with or without 

 an added dye. 



MEVES' Victoria Green. Add a " small " quantity of Victoria 

 green (malachite green) to a 4 per cent, iodic acid solution. Place 

 a drop on a slide with the cells to be examined (Anat. Anz., Bd. 

 xxvi). 



Osmicated solution of Ripart and Petit, cf . 90, recommended to 

 leave out the acetic acid of the original formula. 



Dahlia saturated solution in 0-75 per cent. NaCl. Stains mito- 



