HYDROKOLLAG 



161 



ICTERUS INDEX 



HYDROGEN ION INDICATORS— Conitnued 



Indicator 



Chlorphenol red* 

 4.7 N/20 NaOH 



Bromcresol purple* 

 3.7 N/20 NaOH 



Bromphenol red 

 3.9 N/20 NaOH 



Methyl violet 

 1% aq. or sat. 

 in ealine 



Bromthymol blue* 

 3.2 N/20 NaOH 



Phenol red 

 6.7 N/20 NaOH 



Litmus, purified 

 (Azolitmin) 

 1% aq. or 

 in agar sol. 



Neutral red 

 (Toluylene red) 

 1-2% aq. or sat. 

 in saline 



Cresol red 

 5.3 N/20 NaOH 



Metacresol purple 

 5.3 N/20 NaOH 



Thymol blue* 

 4.3 N/20 NaOH 



pH Range and Colors 

 yellow ♦- 4.8 — red — 6.8 -» purple 



yellow «— 5.4 — 6.6 -♦ purple 

 yellow <— 6.4 — red — 7.0 — ► purple 

 blue- violet <- 6.0 — 7.0 -► violet 



yellow «- 6.0 — 7.4 -* blue 



yellow ♦- 6.6 — 7.8 -» red 

 (6.8 — 8.4) 



(approx.) red ♦- 6.0 — 8.0 -« blue 



(approx.) red «— 6.8 — 8.0 — » yellow 



yellow *- 7.2 — 8.4 —> purple-red 

 yellow ♦-7.4 — 9.0 —» purple 

 yellow ♦- 8.2 — 9.4 -» blue 



Value as Vital Stain 

 Powerful stain, well tolerated. 



Strong stain but rapidly excreted, is toxic 

 and exhibits dichromatism. 



Very strong stain, well tolerated. 

 Weak stain, toxic. 



Weak stain, very toxic to mice, but not for 

 insecte. 



Rapid, intense stain, very well tolerated . 



Slow stain, diffuses poorly, usually de- 

 posits in granules. 



Very weak stain, precipitates out readily 

 in vivo, not toxic if pure. 



Somewhat toxic, not a strong stain. 



Very weak stain, not very soluble. 



Toxic, range too alkaline. 



The indicators starred are perhaps of 

 of widest ordinary laboratory use. To 

 these may also be added cresol purple 

 (yellow <— 7.4-9.4 — >• purple) and phenol- 

 phthalein (colorless <— 8.0-9.8 — »• red- 

 violet). The latter is usually made up 

 in 70-90% alcohol. It should not be 

 used to titrate ammonia. 



Hydrokollag, a particulate material em- 

 ployed for injection of Lymphatic Ves- 

 sels which see. 



Hydrotropes, see Sudan Stains. 



Hydroxy Tri-Phenyl Methanes. These are 

 the rosolic acids. Amino groups of tri- 

 amino tri-phenyl methanes are replaced 

 by hydroxyls making them aciuic in- 

 stead of basic. Examples : aurin (or 

 rosolic acid); red corallin. 



Hydroxybenzene Compounds as cytoplasmic 

 fixatives. Details of use ofpyrogallol 

 and resorcinol in neutralized formal- 

 dehyde solutions are given. The sim- 

 plicity and rapidity of the procedures 

 and the ease of thereafter cutting sec- 

 tions 1-2^1 in thickness are cited as the 

 advantages special attention having 

 been paid to mitochondria and secretion 

 granules (Huseby, R. A., Proc. Soc. 

 Exp. Biol. & Mod., 1946, 61. 122-125). 



Hydroxyquinoline test for iron, see Iron. 



Hypophysis, see Pituitary. 



Hypoxanthine, see Murexide test under 

 Purines. 



Ice-crystal Artefacts in normal and chroma- 

 tolj'tic anterior horn cells (Gersh, I., 

 and Bodian, D., Biological Symposia, 

 1943, 10, 163-184). 



Icterus Index is a simple measure of the 

 degree of yellow color of blood plasma, 

 or serum, in comparison with standard 

 potassium bichromate solutions. Make 

 up in tubes of same thickness and bore 

 as hematocrit tubes a series of unit 

 dilutions of the bichromate solution 

 Unit 1 = 1 gm. potassium bichromate 

 in 10,000 cc. aq. dest.. Unit 3 = 3 gm. 

 in 10,000 cc. Unit 5 = 5 gm. in 10,000 

 cc. etc. The plasma of centrifuged 

 blood in hematocrit is compared with 

 these. If it has a color corresponding 

 to, say, Unit 5 of the bichromate solu- 

 tion the icterus index is considered to 

 be 5. The normal value of the icterus 

 index is usually given as 4-7 units. 

 The measure being that of color, and, 

 since increase in color can bo caused by 

 substances other than bilirubin, the in- 

 dex is not a specific measure of bili- 

 rubinemia. Lipochromes can increase 

 the index. If the blood is unusually 



