TUNGSTIC ACID 



362 



ULTRACENTRIFUGES 



Tungstic Acid, a stable soltiuon (Abraham- 

 son, E. M., Tech. Bull., 1940, 1, 75). 



Turnbull Blue reaction for iron. Same as 

 Berlin blue except use K ferricyanide 

 and HCl. 



Turpentine. Not advised as clearing agent. 

 See test for Alcohol absolute. 



Typhus Fever rickettsiae in lungs of mice. 

 (Nyka, W., J. Path. & Bact., 1945, 52, 

 317-324). Fix in 10% neutral formalin. 

 Stain sections in 1:10,000 aq. methyl 

 violet 30 min. to 1 hr. Differentiate in 

 acetic acid (2 drops glacial acetic in 

 100 cc. aq. dest.) till cytoplasm is de- 

 colorized. Counterstain in 1 : 10,000 aq. 

 metanil yellow for few seconds. Dehy- 

 drate in acetone, clear in xylol and 

 mount in neutral medium (say immer- 

 sion oil). Rickettsiae, violet. 



Tyrian Purple. The ancients prized this 

 dye very highly. Said to have been 

 discovered when a sheep dog of Hercules 

 bit into a shellfish and stained his mouth 

 bright red, this wonderful dye was first 

 produced for local use in Crete about 

 B.C., 1600, and was later distributed by 

 the Phoenicians bringing business to 

 Tyre; hence the name Tyrian purple. 

 Pliny has given a detailed description 

 of its preparation. Factories for ex- 

 traction of the dye from Murex trunclus 

 were established by the Phoenicians at 

 many points in the Mediterranean 

 basin, chiefly at Tyre, Tarentum and 

 Palermo, and trading points at Cadiz, 

 and in present day Morocco. Tyrian 

 purple became the "royal color" em- 



Eloyed by royalty in Persia, Babylon, 

 ledia and Syria. The robes of Greek 

 generals were purple, likewise those of 

 their Gods. Jewish tabernacle decora- 

 tions were colored by a bluish type of 

 Tyrian purple. The sails of Cleo- 

 patra's barge were colored purple. Ac- 

 cording to a decree by Caesar Augustus 

 none in the Roman Empire but the Em- 

 peror and his household could wear 

 purple (Leggett, W. F., Ancient and 

 Medieval Dyes. Brooklyn: Chemical 

 Publishing Co., Inc., 1944, 95 pp.). 



Tyrode solution. NaCl, 0.8 gm.; KCl, 

 0.02 gm.; CaClo, 0.02 gm.; MgCh, 0.01 

 gm.; NaHjPOi, 0.005 gm.; NaHCO,, 

 0.1 gm. (giving pH about 7.5-7.8) ; 

 dextrose, 0.1 gm.; aq. dest., 100 cc. 

 Solution cannot be boiled but can be 

 passed through a Berkfeld filter. 



Tyrosine Reaction. The procedure of Serra 

 and Lopes which gives better results 

 than the Millon Reaction is specified as 

 follows by Serra, J. A., Stain Techn., 

 1946, 21, 5-18: Prepare tissue as de- 

 scribed under Ninhydrin Reaction. 



"1. Immerse the objects for 30 min- 

 utes in a few milliliters of the mercuric 

 solution (composition: HgS04, 7.5 g.; 



HgClz, 5.5 g. ; NajSOi, 7.0 g. ;— dissolved 

 in 85 ml. of distilled water to which 

 12.5 g. of concentrated H2S04 is added; 

 after dissolving dilute to 100 ml. with 

 distilled water). Perform the treat- 

 ment in a small glass stoppered bottle, 

 placed in a water bath which is main- 

 tained at 60°C. 



"2. After the 30-minute treatment, 

 cool the bottle in running water and 

 allow to stand at room temperature for 

 10 minutes. 



"3. Dilute the mercuric solution in 

 the bottle, by addition of an equal vol- 

 ume of distilled water. 



"4. Develop the color, adding now 

 some drops of a freshly-prepared 1 M 

 solution of sodium nitrite (6.9 g. NaN02 

 in 100 ml. of water). 



"The coloration attains its maximum 

 in 3 minutes and lasts for some months, 

 though it fades gradually with time. 

 The materials are mounted and ob- 

 served in pure glycerin, where they can 

 be squeezed or sc^uashed, if necessary. 



"Tne reaction is principally due to 

 the presence of tyrosine in the protein 

 molecule, and is also produced by other 

 phenolic compounds. The method here 

 described gives with tryptophane only 

 a transient coloration, which lasts no 

 more than a few minutes; it is hoped, 

 therefore, that by this procedure this 

 histochemical test reveals only the tyro- 

 sine in the proteins." 

 Turnick, see Aceto-Orcein-Fast Green. 

 Ultracentrifuges — Written by H. W. Beans, 

 Dept. of Zoology, State University of 

 Iowa, Iowa City. September 27, 1951 — 

 Few instruments are more essential to 

 certain phases of biological and medical 

 laboratory analj^sis and research than 

 the centrifuge. However, because of 

 the relatively low centrifugal force 

 generated by this instrument, its use- 

 fulness is limited to the displacement 

 of materials within living cells of rela- 

 tively low viscosity and to biological 

 materials within the test tube that 

 differ greatly in their relative densi- 

 ties. Recent improvement of the elec- 

 trically driven laboratory type centri- 

 fuge has however, resulted in machines 

 capable of generating forces of the order 

 of 10,000 to 30,000 times gravity. It 

 was this type centrifuge that Bensley 

 and Hoerr used to separate and analyze 

 mitochondria (Anat. Rec, 1934, 60, 

 251), a technique which paved the way 

 for the important discovery that mito- 

 chondria are the carriers of all the im- 

 portant oxidative enzymes (Green, D. 

 E., Scientific American, 1949, 181, 48). 



The development of the ultracentri- 

 fuge has provided a tool for the study 

 of the components of living cells of 



