ETHYL EOSIN 



121 



EYES 



acids appear to differ from the true 

 lipases, which act upon long-chain 

 substrates, and from cholinesterase. 

 Gomori, G. (Proc. Soc. Exp. Biol, and 

 Med., 1945, 58, 362-364, and ihid, 

 1949, 72, 697-700) has devised a method 

 for localizing lipase. Nachlas, M. M. 

 and A. IM. Seiigman (J. Nat. Cancer 

 Inst., 1949, 9, 415-425) believe the 

 histochemical methods do not differen- 

 tiate a true lipase, but only a nonspe- 

 cific esterase. They describe a new and 

 vivid method for this enzyme, based 

 upon the hydrolysis of the acetyl ester 

 of naphthol and staining the liberated 

 naphthol by diazotization. Seiigman, 

 A. M., M. M. Nachlas, L. H. Man- 

 heimer, O. M. Friedman and G. Wolf. 

 (Ann. Surg., 1949, 130, 333-341) describe 

 the development of specific methods 

 for a number of hydrolytic enzymes. 



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

 eosin Y. Sold often as alcohol soluble 

 eosin. See Eosins. 



Ethyl Green (CI, 685) . This is, Hke 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 he.xaethyl 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 Heidenliain's modification 

 of Mallory's ethyl-violet orange G after 

 formalin fixation. 



Ethyl Violet-Biebrich Scarlet, see Bowie's 

 stain for pepsinogen. 



Ethylene Glycol Mono-Ethyl Ether = 

 Cellosolve. 



Euchrisine, see Acridine Orange. 



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). 



Exfoliative Cytology, see Papanicolaou 

 Techniques. 



Exogenous Pigments, classified by color, 

 Lillie, p. 134 



Extracellular fluid or phase, see Chloride. 



Exudates, see Agar infiltration to hold 

 materials in place, also Papanicolaou 

 Techniques. 



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 fi.xative 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 is 

 also easier in celloidin because one can 

 see through it fairly well. 



If, on the other hand, preparations are 

 needed of small parts of the eye these 

 parts should be carefully dissected out 

 and the paraffin technique employed. 

 Much time will be saveu by following 

 the excellent suggestions made by S. L. 

 Polyak, The Retina. Univ. of Chicago 

 Press, 1941, 607 pp. and by G. L. Walls 

 (Stain Techn., 1938, 13, 69-76). 



Dr. Polyak in a letter dated April 19, 

 1946 calls attention to the advisability 

 of soaking celloidin blocks in oil as first 

 described by Apdthy, S., Zeit. f. wis. 

 Mikr., 1912, 29, 464. The same method 

 is well presented by Kranse, R., Enzyk. 

 d. Mikr. Technik., 3rd edit., 1926, 1, 

 281. For the investigation of perme- 

 ability, oxidation-reduction potential, 

 enzyme sj'stems, and such properties, 

 see Friedenwald, J. S. and Stiehler, 

 R. D., Arch. Ophth., 1938, 20, 761-786. 

 Useful data are to be found in Kurzes 



