PICRIC ACID 



270 



PINEAL 



^'^ tion of these resins, the manufacturer 



•-, fe. (Pennsylvania Industrial Chemical 



;^'j: Corp., Clairton, Penn.) is not interested 



,, ^in packaging for such small specialty 



,^. sale. However, one of the Piccolytes 

 ("S-115") is on the market under the 

 name of "Harleco Mountant" (Hart- 

 man-Leddon Co., Philadelphia). Pos- 

 sibly, one of lower softening point than 

 S-115 would have been a better choice 

 for general use. 



Picric Acid is a very important ingredient of 

 several fixatives. It penetrates rapidly 

 and serves to some extent as a mordant 

 like potassium bichromate. See Bouin's 

 fluid. Picric acid staining of chromo- 

 phobe bodies of Lipschutz (Schiller, 

 Virchow's Arch., 1930, 278, 663-689). 



Picro-Carmine (Ranvier) . There are many 

 sorts most of them based on Ranvier 's 

 original formula: Add carmine (dis- 

 solved in ammonia) to sat. aq. picric 

 acid to saturation. Evaporate to ^ 

 original volume, cool, filter out ppt. and 

 evaporate filtrate to dryness. The 

 resultant red crystalline powder is 

 picro-carmine. Make a 1% aq. sol. for 

 staining. If overstained decolorize with 

 0.2% hydrochloric acid. This is an 

 excellent and very popular stain. It 

 colors keratohyalin very brightly (Lee, 

 p. 146). 



Picroformaldehyde Formic Acid for fixation 

 (Lillie, R. D., J. Tech. Methods, 1944, 

 24, 35-36). Formaldehyde (37% solu- 

 tion), 10 cc, formic acid, 5 cc. and sat. 

 aq. picric acid, 85 cc. is recommended 

 as a substitute for Bouin's Fluid. It 

 decalcifies femurs of mice well in 48 

 hrs., provides sections adapted to 

 Romanovsky staining, and in general 

 acts like Bouin's fluid. 



Picro-Formol, see Bouin's Fluid. 



Picro-Indigo-Carmine is a much used stain. 

 Lee (p. 433) advises 3 parts sat. indigo- 

 carmine in 70% ale. and 1 part sat. picric 

 acid also in 70% ale. 



Picro-Mallory. Several fine modifications 

 of Mallory's connective tissue stain 

 using picric acid (McFarlane, D., Stain 

 Techn., 1944, 19, 29-37). 



Picro-Nigrosine for muscle. After alcohol 

 or Bouin fixation, stain sections in sat. 

 nigrosine in sat. aq. picric acid. Muscle 

 yellow, connective tissue black. 



Picro-Sulphuric fixative, see Kleinenberg's. 



Pigments, general reviews: Bergmann, E. 

 Ergeb. d. Physiol., 1933, 35, 158-300; 

 Lederer, E., Biol. Rev., 1940, 15, 273- 

 306 (invertebrates). See Aposiderin, 

 Bacterial, Bile Pigment, Bilirubin, 

 Biliverdin, Carotin, Carotinalbumins, 

 Carotinoids, Ceroid, Chromolipoids, 

 Cytochrome, Cytolipochrome, Cytosid- 

 erin, Exogenous, Hematin, Hematoi- 

 din, Hematoporphyrin, Hemofuscin, 



Hemoglobin, Hemosiderin, Trichosid- 

 erin, Iron Pigments, Lipochrome, Lipo- 

 fuscin (wear and tear pigment), 

 Malarial Melanins, Parhemoglobin, 

 Porphyrins, Rhodopsin, Scheele's 

 Green, Sulfmethemoglobin, Schwein- 

 furt Green, Ultramarine Green and 

 Verdigris. 



Pinacyanol (CI, 808) — sensitol red — A basic 

 xanthene dye of the cyanine group. 

 Proescher, F., Proc. Soc. Exp. Biol. & 

 Med., employed the Eastman Kodak Co. 

 product of which a 0.1-0.5% solution in 

 absolute ethyl or methyl alcohol for 5- 

 10 sec. stains frozen sections brightly. 

 Wash in water, mount in glycerine. 

 Chromatin, blue violet; protoplasm, 

 purple; connective tissue, red; elastic 

 tissue, black violet; muscle, bluish 

 violet to purple; amyloid, red; etc. 

 Hetherington, D. C, Stain Techn., 

 1936, 11,, 153-154, used pinacyanol as a 

 supravital stain for mitochondria in 

 blood cells. 



Pineal. Staining pineal parenchyma by a 

 modified Hortega method after paraffin 

 embedding — Written by W. M. Shank- 

 lin, American University of Beirut, 

 Beirut. March 30, 1951— Fix the gland 

 as soon as it is removed in 10% formalin 

 (Merck blue label 40%) 3 days at room 

 temperature of about 24°C. Wash for 



2 hrs. in aq. dest. to which 6 drops of 

 ammonium hydroxide are added for 

 each 100 ml. Wash again in aq. dest. 

 for a few minutes and dehydrate the 

 gland in 70%, 80%, 95% and absolute 

 alcohol, leaving 3 hrs. in each. Clear 

 in cedar oil over night, followed by 

 pure xylene for half an hr. Infiltrate 

 with paraffin (melting point 48°C.) for 



3 hrs. Embed in pure paraffin. Cut 

 sections 7-10 m, fix to slides by the 

 albumen-water method and dry thor- 

 oughly. Heat the slide gently to soften 

 the paraffin and pass through 2 changes 

 of xylene. Pass slides through abso- 

 lute alcohol, 95% and 80% alcohol 1-2 

 min. in each. Wash in 3 changes aq. 

 dest. for 3 min. each. Place slides in 

 10% aq. silver nitrate to which 3 drops 

 of pyridine for each 10 ml. are added 

 and keep in the dark at room tempera- 

 ture 24°C. for 24 hrs. Wash in aq. 

 dest. and sensitize by placing in 5% 

 sodium sulfite 1 hr. This step may be 

 omitted, but sometimes this is neces- 

 sary as it acts as a rejuvenator. Wash 

 in aq. dest. to which 2 drops of pyridine 

 for each 10 ml. are added for 1 to 2 

 min. followed by 2 changes aq. dest. 

 Impregnate in strong silver carbonate 

 at room temperature for 2 to 5 min. 

 Formula: 10% aq. Silver nitrate (pure 

 crystals) 100 ml., 5% aq. Sodium car- 

 bonate (pure) 300 ml., Ammonium 



