ENZYMES 



89 



EOS IN.' y 



azure dyes, including neutral red, like- 

 wise precipitate pepsin, trypsin, crep- 

 sin and papain. The linkage of enzyme 

 to dye is, he thinks, through the basic 

 nitrogen of the heterocyclic ring of the 

 latter. In view of these observations, 

 and the coloration of mitochondria with 

 janus green, Marston suggests that the 

 mitochondria contain proteolytic en- 

 zymes. Methods for the enzymatic 

 analysis of purified elementary bodies 

 of vaccinia are described by Hoagland, 

 C. L., Ward, S. M., Smadel, J. E., and 

 Rivers, T. M., J. Exper. Med., 1942, 76, 

 163-173. Two very helpful reviews are 

 recommended: Gersch, I., Physiol. 

 Rev., 1941, 21, 242-266, and Blaschko, 

 H. and Jacobson, W. (Bourne, pp. 189- 

 224). 



Enzymes are coming into their own 

 as technical tools. Ribonuclease in 

 study of the mechanism of the Gram 

 Stain, Hyaluronidase as a Spreading 

 Factor, Lysozyme in detecting the pres- 

 ence of acetyl amino polysaccharide in 

 bacteria, Pectinols in demonstrating 

 chromosomes, Pancreatin in digesting 

 away the cellular components of the 

 spleen leaving onlj^ the framework, and 

 a great many others in specifically hy- 

 drolyzing the substrates on which they 

 act. The enzymatic destruction of the 

 capsules of pneumococci as summarized 

 by Dubos, R. J., The Bacterial Cell. 

 Harvard Univ. Press, 1945, 460 pp. is an 

 instructive example. When the capsu- 

 lar polysaccharide is hydrolysed by the 

 enzyme the pneumococci are made vul- 

 nerable to the phagocytic action of 

 leucocytes. 



Eosinophile Leucocyte (acidophilic " or 

 coarsely granular leucocyte). Can 

 easily be examined while still living in 

 mounts of fresh blood. The dark field 

 is useful. Most frequently studied in 

 Blood Smears, which see. Mitochon- 

 dria are readily stainable with Janus 

 Green. For occasional presence of 

 basophile granules and pigment see 

 Downey, H., Folia Haemat., 1915, 19, 

 148-206. Techniques for rapid experi- 

 mental increase of eosinophiles in 

 circulating blood are described by 

 Banerji, N., Am. J. Med. Sci., 1933, 

 186, 689-693; Chillingworth, F. P., 

 Healy, J. C. and Haskins, F. E., J. Lab. 

 and Clin. Med., 1933-34, 19, 486-494; 

 Hajos, K., Nemeth, I., and Enyedy, Z., 

 Zeit. f. d. ges. Exper. Med., 1926, 

 48, 590-592. 



Eosin B or bluish (CI, 771)— eosin BN, BW, 

 or DHV, eosin scarlet, eosin scarlet B, 

 imperial red, nopalin G, saff rosin, 

 scarlet J, JJ, V — Dibrom derivative of 

 dinitro-fluorescein. Chemistry of 



(Holmes, W. C, Melin. C. G. and 



Paterson, H. R., Stain Techn., 1932, 

 7, 121-127). 



There are several fluorescein dyes 

 and guidance may be needed in the 

 choice of the one best suited for a par- 

 ticular purpose. Conn, H. J. and 

 Holmes, W. C, Stain Tech., 1926, 1, 

 87-95; 1928, 3, 94-104 have made a study 

 of color, acidity and chemical structure 

 and Conn (p. 145) gives further data. 

 Their color increases in depth in this 

 order: eosin Y, ethyl eosin, eosin B, 

 erythrosin B, phloxine and rose bengal. 

 This increase in color is proportional to 

 increase in number of hologen atoms. 

 Their acidity increases in a different 

 order: rose bengal, phloxine, erythrosin, 

 eosin Y and eosin B. (1) When the 

 eosin is to follow in alcoholic solution a 

 basic dye always in aqueous solution 

 (cf. hematoxylin) the more acid and 

 lighter colors are recommended (eosin 

 Y, ethyl eosin and eosin B. (2) When 

 it is to precede in aq. solution a basic 

 dye (cf. methylene blue) also in aq. 

 solution, use phloxin or erythrosin (see 

 phloxine-methylene blue). 



Eosin lOB, see Phloxine B. 



Eosin BN, BW, or DHV, see Eosin B or 

 bluish. 



Eosin J, see Erythrosin, bluish. 



Eosin-Methyl Blue, see Mann's. 



Eosin-Methylene Blue has been employed 

 in many combinations for years. But 

 when the acid dye is applied first, 

 phloxine is preferred to eosin. See 

 therefore Phloxine Methylene Blue. 



Eosin-Orange G — Toluidine Blue for bone 

 marrow, spleen and connective tissue 

 (Dominici, M. C. rend. Soc. biol., 1902, 

 54, 221-223). Stain eosin-orange G 

 (eosin B. A. of Hollborn or eosin yellow- 

 ish of American manufacturers 0.5 gm. ; 

 aq. dest., 100 cc; orange G. 0.5 gm.) 

 7 min. Rinse quickly in aq. dest. 

 Counterstain in 0.5% aq. toluidin blue 

 20-30 sec. Rinse again aq. dest. Dif- 

 ferentiate in 95% ale, dehydrate in 

 abs., clear in .xylol and mount in balsam. 

 Instead of eosin, 0.5% aq. acid fuchsin 

 gives a little sharper contrast. In 

 place of toluidin blue 0.1% Azur A can 

 be employed to advantage. Phloxine- 

 orange G can be tried as a substitute for 

 eosin-orange G. (phloxine 0.12 gm., aq. 

 dest. 100 cc, orange G, 0.3 gm.). The 

 crucial point is the differentiation in 95% 

 ale. This should be quickly checked 

 under the microscope until the time has 

 been determined. 



Eosin Scarlet, see Eosin B or bluish. 



Eosin Scarlet B, see Eosin B or bluish. 



Eosin Y or yellowish (CI, 768). Tetrabrom 

 fluorescein with some mono- and di- 

 brom compounds. This is the usual 

 kind of eosin employed. Eosin Y and 



