PHASE CONTRAST MICROSCOPE 



266 



PHLOXINE-METHYLENE BLUE 



of the immunologic control of phagocy- 

 tosis of erythrocytes by these cells can 

 be provided by using a method de- 

 scribed by Bloom, W., Arch. Path. & 

 Lab. Med., 1927, 3, 608-628. 

 Phase Contrast Microscope. By phase 

 contrast one generally means a system 

 of illumination and phase retardation 

 by means of which phase differences 

 of light waves are converted into ampli- 

 tude differences. Its purpose is to 

 create contrast, thus rendering objects 

 visible which would otherwise be im- 

 possible to see in a bright-field because 

 of e.xcessive transparency. 



The equipment consists of an annular 

 diaphragm in the front focal plane of 

 the condenser and a diffraction plate 

 of special design placed between the 

 components of the objective lens. 

 Phase contrast microscopes, developed 

 in Europe just before the war, have 

 been commercially available in the 

 United States only recently but already 

 an impressive amount of investigation 

 has been reported on biological material 

 (Bennett, A. H., Sci. Monthly, 1946, 43, 

 191-193; Richards, O. W., Cold Spring 

 Harbor Svmposium Quant. Biol., 1947, 

 11, 208-214). Their great usefulness 

 lies in the fact that with their help one 

 can see more clearly than by other 

 means at high magnification and resolu- 

 tion such external and internal cellular 

 structures as surfaces (Ralph, P. H., 

 Anat. Rec, 1947, 98, 219-223, 489-507); 

 vaginal smears (Culiver, A., and Gluck- 

 man, J., J. Obst. and Gynaec, Brit. 

 Empire, 1948, 55, 261-267); centrioles 

 (Buchsbaum, R., Anat. Rec, 1948, 102, 

 19-27) ; mitochondria (Ludford et al., 

 J. Roy. Micr. Soc, 1948, 68, 1-9; Zollin- 

 ger, H. v., Am. J. Path., 1948, 24, 569- 

 589); viral inclusion bodies (Angulo, 

 J. J. et al, J. Bact., 1949, 57, 297-303) 

 etc. in the living stage, or in fixed and 

 unstained material. 



Lack of contrast has always been a 

 problem peculiar to histology and 

 cytology because the refractive indices 

 of cytoplasm and its inclusions are so 

 nearly the same. The classical method 

 of creating color contrast by selective 

 or differential staining is subject to 

 well-known limitations. Phase micros- 

 copy now provides for the first time 

 an effective, reliable method of creating 

 contrast by purely optical means. 

 The chief deterrent to its universal 

 adoption for research is its present 

 high cost, ranging from $500 to $1,000 

 for a microscope and accessories. 

 Moreover special adjustments have to 

 be made for the particular tissue to be 

 examined. You cannot simply take 

 the microscope out of the cupboard 



and get busy in the examination of 

 any old tissue as is customary with 

 the standard bright light microscope. 

 The phase contrast microscope is not of 

 any particular assistance in the study 

 of fixed and stained preparations in 

 which differential tissue transparency 

 is not a factor of primary importance. 



Phenol Compounds, see Azo Reaction, Indo 

 Reaction. 



Phenolase, see Oxidase. 



Phenoloxida ^, see criticism of Dopa Oxi- 

 dase reaction. 



Phenolphthalein. This compound of 

 phthalic acid with phenol and sulfuric 

 acid is an important indicator. Closely 

 related to it is cresolphthalein. 



Phenosafranin (CI, 840) — safranin B extra — 

 This is the simplest of the safranins. 

 It has been used by Moore, E. J., 

 Science, 1933, 77, 23-24_ for staining 

 fungi on culture media or in host tissue. 



Phenosulfonphthalein, use in renal function 

 tests (Shaw, E. C, in Glasser's Medical 

 Physics, 1628-1630). 



Phenyl Methane Dyes. The hydrogen 

 atoms of methane can be replaced by 

 phenyl groups and it is possible to add 

 amino groups to the benzene rings. 

 See di-phenyl methanes, di-amino tri- 

 phenyl methanes, tri -amino tri -phenyl 

 metlmnes, and hydroxy tri -phenyl 

 methanes. 



Phenylene Blue, see Naphthol Blue R. 



Phenylene Brown, see Bismark Brown Y. 



Phloroglucin is 1,3,5-trihj'^droxybenzene. 

 It is obtained in the form of a yellowish 

 white crystalline powder. It protects 

 the organic components of tissues so 

 that acids can be used in higher con- 

 centrations for decalcification. Make 

 sat. aq. sol. phloroglucin and add 

 5-25% of the acid. 



Phloxine (CI, 774)— erythrosin BB or B 

 extra, new pink. 



Phloxine B (CI, 778) — cyanosine, eosin 

 lOB, phloxine TA, N or BB— Conn 

 (p. 154) explains that this differs from 

 phloxine in possessing 4 in place of 2 

 chlorine atoms in phthalic acid residue 

 of molecule. This phloxine B is the 

 one ordinarily used. See Eosins. 



Phloxine Ta, N or BB, see Phloxine B. 



Phloxine-Azure. This resembles Mallory's 

 phloxine-methylene blue. Stain sec- 

 tions after Bouin or Zenker fixation 

 in 2.5% aq. phloxine, 15 min.; wash in 

 water and stain in 0.1% aq. azure A, 

 30 min.; wash in water, differentiate in 

 95% ale. plus few drops xylene colo- 

 phonium; dehydrate in abs., clear in 

 xylol and mount. Particularly good 

 for bone marrow. (Haynes, R., Stain 

 Technology, 1926, 1, 68). 



Phloxine-Methylene Blue. Mallory (p. 86) 

 recommends that phloxine be employed 



