REFLECTING MICROSCOPE 



304 



REISSNER'S FIBER 



hyperchromatic Sternberg Cells are a 

 later development of Reed cells (Ber- 

 sack, S. R., Am. J. Clin. Path., 1943, 

 13, 253-259). The cytoplasmic inclu- 

 sions, reported by Grand, are sugges- 

 tive of virus action. The claim of Sym- 

 mers, D., J. A. M. A., 1945, 128, 1248- 

 1249, that these cells should be called 

 Greenfield Cells in honor of Greenfield's 

 first de.scription in 1878 will probably 

 not be followed. The Phase Micro- 

 scope can be helpful in the study of 

 Reed-Sternberg cells (Hoffmann, J. T. 

 and Rottino, A., Blood, 1950, 5, 74-78). 

 Reflecting Microscope. As is well known, 

 magnified images can be produced by 

 mirrors as well as by lenses. Proposals 

 have been made many times to take 

 advantage of the special properties of 

 mirror systems to create a microscope 

 of a pattern analogous to the reflecting 

 telescope. Such an instrument would 

 be completely achromatic, and thus 

 superior to the best refracting micro- 

 scope objective, the apochromatic, 

 which is corrected for only three colors 

 of chromatic aberration and two colors 

 of spherical aberration. There would 

 be no great loss of light by reflection 

 compared to the considerable loss en- 

 countered in lenses by absorption. 

 Furthermore, a reflecting microscope 

 focused by visible light would also be 

 in focus for ultraviolet and infra-red 

 light, thus simplifying the process of 

 photography. The construction of sev- 

 eral such microscopes has been de- 

 scribed in the literature, but serious 

 consideration was not given to them 

 because their numerical apertures 

 were low and they had but little to 

 offer over the lens type of microscope. 



The rising tide of interest in ultra- 

 violet microscopy has stimulated recent 

 developments in this field. Burch in 

 England (Burch, C. R., Proc. Phys. 

 Soc, London, 1947, 59, 41-49) has de- 

 signed a long focus, reflecting objective 

 with magnification and resolving power 

 equivalent to that of the average 

 "high-dry" lens. This permits one to 

 employ a micro-manipulator and to 

 observe objects behind thick glass 

 walls, such as tissue cultures. 



Another design, originating in Hol- 

 land (Bouwers, A., Achievements in 

 Optics, New York: Elsevier, 1946, 135 

 pp.) has been put into commercial 

 production recently by Van Leer of 

 Pittsfield, Mass. It can be mass pro- 

 duced because, unlike Burch's model, 

 it uses only spherical reflecting sur- 

 faces. 



Bausch and Lomb have also brought 

 out a special reflecting objective (Grey, 

 D. S. and Lee, P. H., J. Opt. Soc. Am., 



1949, 39, 719-728). This instrument 

 combines both lenses and mirrors in 

 order to gain even higher magnification 

 and resolving power. It is apochro- 

 matic from 220 to 800 m/i, and has a 

 working distance of about 1 mm. A 

 reflecting condenser has been designed 

 to match this objective. The whole 

 outfit costs about $1,000. Use of a 

 reflecting microscope for the study of 

 cells is described by Mellors, R. C, 

 J. Nat. Cancer Inst., 1950, 10, 1358-1361. 



Refractive Index. Microscopical deter- 

 mination bystandard liquids. See paper 

 by Kunz, A. H. and Spulnik,J., Re- 

 viewed in J. Roy. Micr. Soc, 1937,57, 

 55. 



Regaud's Fluid. 3% aq. potassium bi- 

 chromate, 20 cc. ; formalin, 5 cc. When 

 this is used for mitochondria fix tissue 

 for 4 days changing every day and then 

 mordant in 3% aq. potassium bichro- 

 mate for 7 days changing every second 

 day. It is a fluid that can be profitably 

 employed for many other purposes. 

 Of these see Giemsa's Stain, Lead, 

 Masson's Trichrome, Romieu Reac- 

 tion and Starch Grains. 



Regaud's Method of iron hematoxylin for 

 mitochondria. Fix tissues in Regaud's 

 fluid, mordant, imbed and section as 

 described under Anilin Fuchsin Methyl 

 Green Method. Run mounted sec- 

 tions down to water and mordant for 

 24 hrs. in 5% aq. iron alum. Rinse 

 quickly in aq. dest. (not tap water) 

 and transfer to hematoxylin (made by 

 dissolving 1 gm. hematoxylin crystals 

 in 10 cc. abs. ale. adding 10 cc. glycerin, 

 80 cc. aq. dest. and allowing to ripen 

 3 weeks). If traces of iron alum are 

 carried to the stain they will do no harm, 

 but if too much enters the hematoxylin 

 a dense black precipitate will form and 

 ruin the hematoxylin. On the other 

 hand, if the sections are washed ex- 

 cessively in aq. dest. too much of the 

 alum will be removed and the hema- 

 toxylin will not stain as intensely as it 

 should. The happy mean must be de- 

 termined. The hematoxylin should be 

 used over again about 10 times. Differ- 

 entiate in 5% aq. iron alum under low 

 magnification. Wash in running tap 

 water (not aq. dest.) 1 hr. This should 

 bring out the blue-black color of the 

 hematoxylin stain. Dehydrate, clear and 

 mount. Various counterstains can be 

 used if desired. Consult Meves' beauti- 

 ful figures of collagenic fibers stained 

 with fuchsin (Meves, F., Arch. f. Mikr. 

 Anat., 1910, 75, 149^208). This is the 

 most permanent stain for mitochondria 

 but lacks the color contrast afforded by 

 anilin fuchsin methyl green. 



Reissner's Fiber, staining reactions of 



