174 PRACTICAL HISTOLOGY. 



stains the nuclei of epithelium, and the protoplasts of 

 connective tissue remarkably well ; nerve cells and axial 

 cylinders, the lung, skin, cornea, tongue, etc., can be 

 beautifully tinged by this agent. It is, however, a somewhat 

 perplexing substance, on account of the difficulty expe- 

 rienced in getting a staining fluid capable of giving a pure 

 violet tinge.* It was introduced by Boehmer. Kleinen- 

 berg's receipt for the solution is the best (Foster and Bal- 

 four's Elements of Embryology, p. 248). 



A. Make a saturated solution of crystallised calcium 



chloride in alcohol (70 per cent), and add alum to 

 saturation. 



B. Make a saturated solution of alum in alcohol (70 



per cent). 



C. Add A to B in the proportion of 1:8. 



D. Make a barely alkaline saturated solution of haema- 



toxylin in water. 



For staining place eight or ten drops of D in a watch- 

 glass half filled with C ; allow the tissue to remain in it 

 until stained of sufficient depth ; then wash in water. 

 Diffuse staining may be removed by immersion in rectified 

 or in methylated spirit, or in a \ per cent solution of alum. 



Tissues stained with logwood are mounted in Farrants' 

 solution, glycerine, or in dammar. 



324. Magenta (rosaniline nitrate) is an extremely use- 

 ful dye, because of its rapidity of action and the sharp 

 definition which it gives to objects. Like carmme, it stains 

 protoplasts, the axial cylinders of white nerve fibres, etc. 

 Unlike carmine, it fades, and is therefore not suitable for 

 permanent preparations. Nevertheless, the colour can be 

 retained for a long time by mounting the stained tissue in 

 one-third per cent watery solution of corrosive sublimate. 

 Two fluids are necessary. 



a. Ordinary magenta fluid prepared thus 



Magenta crystals . . i Decigramme. 

 Rectified spirit . . pCC. 

 Distilled water . . 2I3CC. 



* A good logwood staining fluid may be obtained from Martindale, 

 chemist, New Cavendish Street, London, W. 



