COCHINEAL 



70 



COLOR ESTIMATION 



highly prized was it that Montezuma 

 took as yearly tribute from the State of 

 Huaxyacas (Now Oaxaca) 20 sacks of 

 cochineaL The invading Spaniards 

 were not slow to note the superiority of 

 cochineal over Kermes, the crimson 

 stain in use at home (1523 A.D.)- 

 Charles V of Spain commanded Cortez 

 to inform him immediately "whether 

 what has been reported is true that 

 Kermes were to be found in abundance 

 in New Spain and, if so, could be sent 

 with advantage to Spain". So coch- 

 ineal figured largely in the Aztec 

 tributes to Cortez and the industry 

 became a Spanish monopoly. In 1858 

 A.D. aniline red became a competitor, 

 depressed the sales of cochineal, whicli, 

 latter as a commercial dj'^e, was defi- 

 nitely replaced when azo dyes came into 

 the market about A.D. 1880. (Leggett, 

 W. F., Ancient and Medieval Dyes. 

 Brooklyn: Chemical Publishing Co. 

 Inc., 1944, 95 pp.). See Kermes, Lac. 

 In microscopy cochineal is used 

 mostly for staining in toto of small in- 

 vertebrates. Mayer's alcoholic cochi- 

 neal is a popular preparation made, ac- 

 cording to Lee (p. 149), by powdering 

 5 gm. cochineal with 5 gm. calcium 

 chloride and 5 gm. aluminum chloride to 

 which 100 cc. 50% alcohol and 8 drops of 

 nitric acid (sp. gr. 1.20) are added. 

 Heat to boiling point, cool, sliake oc- 

 casionally during several days and filter. 

 Before staining bring objects to 70% 

 alcohol, destain if necessary in 70% 

 alcohol containing 0.1% hydrochloric 

 acid. Dehydrate, clear and mount in 

 balsam. Nuclei are colored red and 

 other structures a variety of colors from 

 red to deep purple. In some respects 

 it is better than carmine. Neither fade. 



Cochlea, see Ear. 



Coelestin Blue, see Skyblue. 



Coeline, see Skyblue. 



Coeruleum, see Skyblue. 



Colchiceine, different from colchicine, see 

 Ludford, R. J., Arch. f. exper. Zellf., 

 1935-36, 18, 411-441. 



Colchicine, see Mitosis Counts. 



Collagenic Fibers. On boiling they yield 

 collagen. They are also called white 

 fibers in contrast to the elastic fibers 

 which are distinctly yellow. Details 

 can be seen in fresh, unstained spreads 

 of Loose Connective Tissue. The col- 

 lagenic fibers are usuall}'^ more numerous 

 in subcutaneous connective tissue, less 

 highly refractile than the elastic ones 

 and of greater girth. They do not 

 branch though the finer fibrils of which 

 they are composed and which confer a 

 faint longitudinal stria tion sometimes 

 do. The R.C.A. electron microscope 

 reveals a still finer system of collagenic 



fibrils (Scott, G. H. and Anderson, T. F., 

 Anat. Rec, 1942, 82, 445 ; Schmitt, F. O., 

 Hall, C. E. and Jakus, M. H., J. Cell, 

 and Comp. Physiol., 1942, 20, 11-33). 

 On addition of dilute acetic acid they 

 swell except at certain places in their 

 length where they seem to be constricted 

 by circular bands. The fact that they 

 also easily pass from the gel to the sol 

 state on alkalinization and when sub- 

 jected to slight heat is the basis for 

 methods of separating Epidermis from 

 dermis. 



The best stain for collagenic fibers in 

 sections after Zenker fixation is anilin 

 blue in Mallory's Connective Tissue 

 Stain and in Masson's Trichrome 

 Stain. Phosphomolybdic Acid Hema- 

 toxylin also gives a fine coloration of 

 collagenic fibers. See Van Gieson, 

 Buzagio, Biebrich Scarlet and Picro- 

 Anilin Blue of Lillie and Curtis' Sub- 

 stitute for Van Gieson. 



Lillie, R. D., J. Tech. Methods, 1945, 

 No. 25, 45 pp. has performed a very use- 

 ful service in testing the effectiveness 

 of a large series of dyes as collagenic 

 fiber stains in the Van Gieson, Mixed 

 Masson-Van Gieson and Masson-Mal- 

 lory procedures. He found the best to 

 be Naphthol blue-black (CI, 246), Fast 

 Green FCF, Acid Fuchsin (CI, 692), 

 Methyl Blue (CI, 706), Anilin Blue (CI, 

 7U7), Wool Green S (CI, 737) and Vol- 

 amine R CI, 758). For photometric 

 histochemical determination see Sto- 

 well, R. E., J. Invest. Derm., 1945, 6, 

 183-189. 



The technique of microincineration 

 as adapted to collagenic fibers is de- 

 scribed by Allara, E., Bull. d'Hist. 

 Appl., 1938, 15, 220-242. See Tendons. 



Collodions. There are several. See U.S. P. 

 XI. All are solutions of Pyroxylin. 



Colloxylin, see Pyroxylin. 



Colophonium, usually dissolved in turpen- 

 tine is employed to mount sections. 

 Not advised. 



Color Estimation. Accuracy in reporting 

 differential stains and micro-chemical 

 reactions yielding colors is highly de- 

 sirable. The same holds for colors 

 determined by naked eye inspection. 

 A monograph, Ridgway, R., Color 

 Standards and Color Nomenclature, 

 Washington, D. C, 1912 with 53 colored 

 plates, is the accepted standard for 

 comparison. In general, however, it is 

 desirable to achieve some measure of 

 uniformity by limiting oneself when- 

 ever possible to use of the terms recom- 

 mended in the National Formulary VII. 

 Washington: American Pharmaceutical 

 Association, 1942, 690 pp., a publication 

 which is available in most medical 

 libraries: 



