ERYTHROCYTES 



92 



EYES 



Megaloblasts: "... a daughter endo- 

 thelial cell which starts to synthesize 

 hemoglobin." "The megaloblast has 

 maximum basophilia, a moderate num- 

 ber of rod-shaped mitochondria, a trace 

 of hemoglobin, and a nucleus with a 

 minimum of chromatin and conspicuous 

 nucleoli." 



Early erythroblasts: "The young ery- 

 throblast represents a growth phase, 

 with less rapid division, for the cell is 

 much larger than the megaloblast; it 

 contains the maximum number of mito- 

 chondria. The amount of hemoglobin 

 is still small, but sufficient to give a 

 polychromatophilia, predominately 



basophilic in methylene blue-azur. The 

 nucleus has a marked increase in 

 chromatin." 



Late erythroblasts : This cell "is inter- 

 mediate in size between the early 

 erythroblast and the definitive red cell. 

 The nucleus has lost the nucleoli but 

 still has massive chromatin. . . . The 

 increase in hemoglobin is marked and in 

 fixed films the cytoplasm is more 

 acidophilic." 



Normoblasts: "The stage of the nor- 

 moblast is defined as a nucleated red 

 cell after its last cell division. It has 

 a small pyknotic nucleus ready for 

 extrusion or fragmentation." 



Erythrocytometer for measuring the diam- 

 eter of red blood cells. Pijper, A., Med. 

 J. South Africa, 1919, 14, 472 and Lan- 

 cet, 1935, 1, 1152, deserves great credit 

 for the discovery independently of 

 Thomas Young (1813) of a technique 

 for the measurement of small objects 

 utilizing the principle of diffraction and 

 Zeiss has manufactured an instrument 

 on his specifications. Another, the 

 Haden-Hausser erythrocytometer, is 

 made by C. A. Hausser and Son and is 

 sold by Arthur H. Thomas Co., Phil- 

 adelphia (Haden, R. L. J. Lab. & Clin. 

 Med., 1939-40, 25, 399-403). 



Erythrosin B, see Erythrosin, bluish. 



Erythrosin BB or B extra, see Phloxine. 



Erythrosin, bluish (CI, 773)— dianthine B, 

 eosin B, erythrosin B, iodeosin B,pyro- 

 sin B — Fluorescein with 2 iodine atoms. 

 See Eosins. 



Esterase, see method under Lipase. 



Ethyl Eosin (CI, 770). The ethyl ester of 

 eosin Y. Sold often as alcohol soluble 

 eosin. See Eosins. 



Ethyl Green (CI, 685) . This is, like methyl 

 green, prepared from crystal violet but 

 differs from it insofar that an ethyl group 

 is added instead of a methyl one. For 

 most purposes it is a satisfactory sub- 

 stitute for methyl green. 



Ethyl Purple 6B, see Ethyl Violet. 



Ethyl Violet (CI, 682)— ethyl purple 6B— 

 It is hexaethyl pararosanilin, a basic dye 



employed by Bowie, D. J., Anat. Rec, 

 1924, 29, 57 to make a neutral stain with 

 biebrich scarlet for staining islets of 

 Langerhans of fish. Kernohan, J. W., 

 Am. J. Clin. Path., 1931, 1, 399-403 

 has used in Heidenhain's modification 

 of Mallory's ethyl-violet orange G after 

 formalin fi.xation. 



Ethyl Violet-Biebrich Scarlet, see Bowie's 

 stain for pepsinogen. 



Ethylene Glycol Mono-Ethyl Ether = 

 Cellosolve. 



Eunematoda, see Parasites. 



Euperal is, according to Lee (p. 227), a mix- 

 ture of camsal, eucalyptol, paraldehyde 

 and sandrac, n = 1.483 of two sorts 

 colorless and green. Since the green 

 one contains a copper salt it strengthens 

 hematoxylin stains. 



Euporium, see Atomic Weights. 



Evans Blue (T. 1824 Eastman Kodak Co.). 

 Used clinically in man for estimation of 

 blood volume. Vital staining of malig- 

 nant tumors in man (Brunschwig, A., 

 Schmitz, R. L., and Clarke, T. H., 

 Arch. Path., 1940, 30, 902-910). It is 

 not taken in by red cells and hence is 

 valuable for the determination of plasma 

 volume (Gregersen, M. I., and Schiro, 

 H., Am. J. Physiol., 1938, 121, 284-292. 

 See Blood Cell Volume. 



Excelsior Brown, see Bismark Brown Y. 



Excretion contrasted with secretion (Cow- 

 dry's Histology, p. 259). 



Extracellular fluid or phase, see Chloride. 



Eyes. Techniques easily used for other 

 parts of the body require special care in 

 the case of the eye. When sections 

 through the entire eye are required it is 

 important to see that the fixative chosen 

 penetrates properly and that the normal 

 shape of the organ is retained. Fixation 

 by vascular injection may be helpful but 

 it is not sufficient because so much of the 

 eye is avascular. After removal of the 

 eye from the orbit, whether previously 

 injected or not, and after the dissecting 

 away of unwanted muscular and other 

 tissues, it should be immersed in the 

 fixative. This will harden the outer 

 coats somewhat. After a few minutes 

 small amounts of the fixative should be 

 injected by a hypodermic syringe into 

 both chambers choosing locations not in 

 the plane of the proposed sections and 

 providing opportunity for fluid also to 

 leave. Then, with a sharp razor blade, 

 a deep cut should be made to permit free 

 entrance of the fixative. After several 

 hours, more of the tissue on either side 

 of the plane should be cut away. Im- 

 bedding in celloidin by the rapid method 

 is preferable to paraffin since it affords 

 much needed support to the less dense 

 parts. Orientation for sectioning ia 



