404 STJ-CIAL MICROSCOPIC TECHNIQUE. 



14. Orcein is to be considered as a specific stain for r/V/,s7/V 

 tisme. According to Unna's new method, the following fluid 

 is used: 1 part of orcein; 100 parts of absolute alcohol; 1 part 

 of HC1. Sections are placed in this fluid at 30 C. for from 

 ten to fifteen minutes, and then washed in alcohol. Elastic 

 fibres are stained dark brown. 



Isolated elastic fibrils can be obtained by macerating a piece 

 of the ligamentum nuchse of an ox in a solution of pancreatin. 

 If a piece 1 cm. in size be used, fibrils can be obtained in all 

 stages of disintegration, depending on how near the centre of 

 the piece they are situated. Specimens showing the mem- 

 branes can be obtained by boiling ligamentum nuchas in con- 

 centrated HC1, and pouring the whole out into a large quantity 

 of cold water just before disintegration takes place (Mall). 



Magenta is used to stain fresh specimens of elastic tissue. 



Mallory's Elastic Tissue Stain. Sections of tissue hardened 

 in corrosive sublimate or Zenker's fluid are stained for from 

 one to three minutes in aqueous acid fuchsin (^"iV P er cent.). 

 After washing in water, they are transferred for one minute to 

 1 per cent, phosphomolybdic acid, and again washed in water. 

 After this they are placed for from two to twenty minutes in 

 the following mixture : an ill n- blue in water, 0.5 part ; orange- 

 (I, 2 parts; oxalic acid, 2 parts; water, 100 parts. They are 

 then washed, dehydrated, and cleared. 



15. Reticulum is obtained best by digesting frozen sections 

 of lymph gland, kidney, spleen, etc., in pancreatin. After 

 twenty-four hours the sections are placed in a test-tube of water 

 and shaken until the cells are displaced. They are then spread 

 out on a slide, allowed to dry, and stained with acid fuchsin 

 and picric acid (Mall). 



16. Fat is stained by osmic acid, or Sudan III. It may 

 be counterstained with safranin. 



17. Hyaline cartilage may be obtained from the costal car- 

 tilages of young individuals ; elastic cartilage, from the outer 

 ear or epiglottis ; fibrous cartilage, from the intervertebral 

 ligaments or the point of insertion of the ligamentum tere> 

 femoris. 



