PRESERVING AND PREPARING PATHOLOGICAL SPECIMENS. 59 



PICRO-ACID FUCHSIN ( Van Gieson' s Stain}. This double staiu, first 

 suggested by Van Gieson, especially for the nerve tissue, has wide ap- 

 plications in both normal and pathological histology, and is most useful 

 when following a deep hsematoxylin stain. 



It colors the fibrillated connective-tissue fibres and the neuroglia in 

 general a bright or garnet red, and also the axis cylinders and ganglion 

 cells. Myelin, muscle fibres, and certain other cells are stained yellow, 

 while the nuclei after the haematoxylin stain are brownish-red in color. 

 Van Gieson 's stain is also of value, although its limitations in this par- 

 ticular are not yet fully determined, as a coloring-agent for hyalin, 

 amyloid, colloid, and muciii in the tisues. As a differential stain for 

 fibrillated connective-tissue fibres it is of value in the study of various 

 tumors and especially of the sarcomata. 



It is commonly prepared in two strengths, the stronger for use espe- 

 cially in nerve-tissue staining, the weaker for general purposes. The 

 formulae and method of using as suggested by Freeborn 1 are as follows: 



Picro-acid Fuchsin. 

 Stronger solution 



One-per-cent aqueous solution Acid Fuchsin, . . .. . 15 c.c. 

 Saturated aqueous solution Picric Acid and Water, . each 50 " 



Weaker solution 



One-per-cent aqueous Acid Fuchsin, . . . . 5 " 



Saturated aqueous solution Picric Acid, . . / . , . . 100 " 



^The tissues may be hardened either in alcohol, or in Orth's fluid, or 

 in formalin. 



Sections are first stained deeply with haematoxylin, washed in water, 

 and put into the staining fluid, in which they remain for varying periods, 

 depending upon the tissue and the strength of the stain, but in general 

 from one to five minutes. The sections are now rapidly dehydrated by 

 alcohol, cleared with oil of origanum, and mounted in balsam. 



MALLORY'S ANILIN BLUE STAIN. This stain is especially useful in 

 bringing out in blue the fibrillae and reticulum of connective tissue, 

 though various hyaline substances are similarly colored. The nuclei, 

 protoplasm, elastic fibres, axis -cylinders, neuroglia-fibres, and fibrin are 

 stained red ; while red blood cells and myelin-sheaths are yellow. 



The details of the method are as follows : * 



1. Fix in corrosive sublimate or in Zenker's fluid. 



2. Embed in celloidin or paraffin. 



3. Stain sections on a 1.20 to 1.10 of a oue-per-cent aqueous solution 

 of acid fuchsin one to three minutes. 



4. Wash in water. 



1 Fi-eeborn, Transactions New York Path. Soc., 1893, p. 73. 



2 See Mallory and Wright, Pathological Technique, 1901, p. 304. 



