70 THE MICROSCOPIST. 



Blue Fluid from Indigo Carmine. 



Oxalic acid, 1 part. 



Distilled water, 20-30 parts. 



Indigo carmine to saturation. 



Logwood Violet Fluid. 



1. Haematoxylin, ...... 20 grains. 



Absolute alcohol, $ ounce. 



2. Solution of 2 grains of alum to 1 ounce of water. 



A few drops of the first solution to a little of the second in a watch- 

 glass, etc. 



Picro-Carmine Fluid. Filter a saturated solution of 

 picric acid, and add, drop by drop, strong ammoniacal 

 solution of carmine till neutralized. 



Nitrate of Silver Fluid. Fresh membranous tissues, 

 exposed to 0.5 to 0.2 per cent, solution of nitrate of silver, 

 washed and exposed to light, often show a mosaic of epi- 

 thelium, etc. 



Osmic Acid. y^th to 1 per cent, solution stains the 

 medulla of nerves, etc., black. 



Chloride of Gold. The solution should be similar to that 

 of nitrate of silver. Exposure to light stains the nerves, 

 etc., a violet or red color. 



Prussian Blue. After immersing a tissue in 0.5 to 1 

 per cent, solution of a protosalt of iron, dip it in a 1 per 

 cent, solution of ferrocyanide of potassium. 



Other Staining Fluids. Marked effects are often pro- 

 duced by the use of the violet, blue, and other inks in the 

 market. Thus I succeeded in some demonstrations of 

 nerve plexuses in muscle better than in any other way. 

 I suspect the particular ink employed contained a large 

 per cent, of soluble Prussian blue. 



4. INJECTING FLUIDS. 



For opaque injection several plans have been devised. 

 Resinous and gelatinous substances, variously colored, are 



