EAR 



84 



ELECTRICAL RESISTANCE 



157. This method has been used for 

 ascertaining damage to the organ of 

 Corti and for measurements of the 

 length of the organ of Corti in man by 

 Hardy, M., Am. J. Ai)at., 1938, 62, 291- 

 311. A simple technique for measuring 

 the length of the basilar membrane is 

 reported by Keen, J. A., J. Anat., 1939- 

 40, 74, 524-527. 



Various methods of reconstruction 

 have been employed particularly for 

 studv of development of the ear. See 

 Bast, T. H., Arch. OtoL, 1932, 16, 19-38 

 and others. Casts of the labyrinth 

 have been made of a number of different 

 materials including Wood's metal, wax, 

 rubber and so forth. Cummins, H., 

 J. Comp. Neurol., 1924-25, 38, 399-459 

 used mercury for this purpose. See 

 Endolymph. 



Ectoplasm. Cytoplasm lying immediately 

 internal to the plasma membrane. It 

 is usually gelled, and, being free from 

 various formed bodies present in the 

 endoplasm, has a clear hyaline appear- 

 ance. 



Egg, inoculation of lien's eggs, see Chorio- 

 allantoic Membrane. Egg of helminths, 

 see Floatation Techniques. 



Ehrlich-Biondi Stain, known also as the 

 Ehrlich-Biondi-Heidenhain mixture, is 

 one of the classical stains. 



Add 20 cc. sat. aq. acid fuchsin and 50 

 CO. sat. aq. methyl green to 100 cc. sat. 

 aq. orange G agitating the fluid while 

 doing so. Add 60-100 cc. aq. dest. The 

 diluted mixture should redden slightly 

 if a little acetic acid is added. A drop 

 placed on filter paper should be bluish 

 green at the center and orange at the 

 periphery. If there is an outside red 

 zone too much fuchsin has been used. 

 Stain sections of sublimate fixed tissues 

 12-24 hrs. Do not wash in water but 

 dehydrate quickly. Clear and mount. 

 This stain gives beautiful results when 

 properly employed but it is fickle. 

 Many helpful suggestions are given in 

 Lee, p. 179. 



Ehrlich's Acid Hemaloxylin. Dissolve 2 

 gm. hemato.xylin in 100 cc. 95% alcohol 

 and add; aq. dest., 100 c.; glycerin, 100 

 cc; ammonium (or potassium) alum, 3 

 gm., glacial acetic acid, 10 cc. Ripen 

 by exposure to air (but not dust) 2 or 

 3 weeks, or immediately by addition of 

 0.4 gm. sodium iodate. 



Ehrlich's Aldehyde Reagent. 2 gms. para- 

 dimethylamino-benzaldehyde in 100 cc. 

 20% aq. hydrochloric acid. See Uro- 

 bilin. 



Ehrlich's Triacid blood stain. This, also, 

 is one of the classic stains, now seldom 

 used. It contains methyl green, orange 

 G and acid fuchsin; but methj-l green 

 is a basic dj'e so that it is not made up of 

 three acid dj'cs. Ehrlich explained that 



it is so called "because in it all the three 

 basic groups of the methyl green are 

 combined with acid dye-stuffs" (Lee, 

 p. 167) with which modern chemists do 

 not agree. Air dried smears are fixed 

 by heat (110°C) about 2 miu.; stained 

 in triacid (Griibler) 5 min.; washed in 

 aq. dest. until no more color is extracted 

 and dried with smooth filter paper. 

 Said to color neutrophile granules and 

 leave azur granules unstained. 



Eimeria, see Coccidsa. 



Elastic Fibers. Viewed singly in fresh 

 unstained spreads of Loose Connective 

 Tissue these fibers have a faint yellow 

 color, are thinner and more highly re- 

 fractile than collagenic fibers. More- 

 over they are optically homogeneous, 

 branch repeatedly to form networks and 

 do not swell when subjected to dilute 

 acetic acid. To demonstrate them in 

 sections a choice can be made from 

 several quite specific stains including 

 Weigert's Resorcin Fuchsin, Verhoflf's 

 Elastic Tissue Stain, Unna's Orcein 

 Method, Krajian's Congo Stain. 



Elastic Properties, see Surface Tension. 



Elastica-Trichrome Stain. In order to 

 demonstrate elastic fibers with equal 

 clearness to the smooth muscular and 

 collagenic fibers, especially in the walls 

 of blood vessels, a useful combination 

 of Weigert's elastic tissue stain and 

 Masson's trichrome stain has been 

 worked out by Mendeloff, J., Am. J. 

 Clin. Path., 1943, Tech. Suppl. 7, 65. 

 Deparaffinize sections in usual way, 

 wash thoroughly in water and stain in 

 Weigert's Resorcin Fuchsin mixture for 

 CO rain. Wash quickly in Acid Alcohol, 

 dehydrate and differentiate in abs. ale. 

 till section is only faintly red. Pass 

 through 70% ale. to aq. dest. and stain 

 in Harris' Alum Hematoxylin 8 min. 

 Differentiate in water 5 min. Stain in 

 Ponceau acid fuchsin mixture (see Mas- 

 son's Trichrome) 5 min. Wash thor- 

 oughly aad place in 3% aq. phospho- 

 tungstic acid, 10 min. Wash again 

 thoroughly in water and stain with 

 light green. Transfer directly to 1% 

 acetic acid, 3 min. Do not wash but 

 dehydrate, clear and mount in Gum 

 Damar. Elastic tissue, blue-black; 

 smooth muscle, red; collagen, green. 



Electric Tissues of fishes, methods for are 

 given by Dahlgren (McClung, p. 434). 



Electrical Resistance and capacity or 

 Impedence. By employing alter- 

 nating currents of varying frequencies 

 figures for apparent resistance and 

 capacity can be obtained. Red cells, 

 yeast cells, ova etc. have been investi- 

 gated. The technique is not micro- 

 scopic but the data iiave an important 

 bearing on structure. In view of the 

 wide variety of cells studied it is inter- 



