Let's do a little counting

in liquid scintillation.

Model X- $15,000

Beckman- $ 7,995(at left)

Minor

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Beckman systems are easierto use. By far. Just oneknob does all the work of 76knobs on Model X. Almost

unbelievable. But true.And speaking of counting,Beckman systems doit faster. And with greaterefficiency and reliability.The analytical performanceis far superior to anyother. Unbelievable? Let usprove it.

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168SINE,VL 5

1608 SCIENCE, VOL. 154

THE KLETT FLUORIMETER

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they laughedwhen I sat downat the Warburg

I

and Ikeda investigated the proteins inthe lens of several species representingfish, amphibians, reptiles, birds, andmammals by the techniques of immuno-electrophoresis, immunodiffusion, and atwo-dimensional polyacrylamilde gelelectrophoresis. They fouLnd that thecrystallins are specific for the lens.Alpha. beta, and gammai crystallinsare present in fish, amphibianis. aindImammals while alpha, beta and deltacrystallins are characteristic of reptile,Ind bird lenses. The most complex ol'these iare the beta crystallins which, inthe chick, comprise eight or nine pro-teins of similar size and alntigeniic prop-erties but w ith ditl'erenit electropho-retic mlobilitics.

Alexander Kenny a.nd G. Noel CuLr-rie (West Virginia University) reportecdon calciumn and phosphorouLs metaho-lism in the rat lens. It had previouslxbeen established that calciulll conicen-tration increases in lenscs with eitheispontaneoLlslv occurl-ing or1 experi-mentally prodLuced catar.acts. This shiftin calciuLml is counterbalanced by adrop in phosphorouLS. aLnd is accomn-panied by a decrease in dry weightand an increase in water content inthe lens. Earliei workers had suLggestedthat the parathy roid gla-ne.ds were in-volved in the reggulationi of lens calciuLm1in the dog, chronic thyroparathyroidec-tomy restulting in an incre'ase in lenscalciulll. Kenny and CuLrric failed toconfirmn this finding in the rat. How-ever, they we rer able to show that achronic respiratory infection in ratscaLused fluctuLations in the nornial levelsof calciumil and phosphorouLs in thelens. When rats were treatecd \vith along-acting peniicillin prepar-ationi. itwas possible to stabilize the levels ofthese elements in the lens at nor-miialvaluLes. Under these conditions, neither-parathyroidectomy nor thyroparathy-roidectomy resLilted in any change incalciuLnm or phosphorotus levels in thelens.

Edwx ard Cotlier and Jean Fox (Wash-ington University) described the isolfL-tion of rubella virtus froni the lensof huLm.an congenital rubella syn-cdromles. Congenital cataracts wereamon*g the many anonmalies noted ininfants born to mothers who had beeninfected with rubella virus dluring thefirst trimester of pregnancy. Tissue cuLl-ture and Echo-I 1 interference tech-niques were used to demonstrate thatthe rubella virus was recoverable fromthe lens and aqueous humor of chil-dren as old as 9 to 10 months of

age. From the times at which themothers of affected children wereknown to have contracted the virus,it is possible to conclude that the virusparticle must have traversed the lenscapsule in order to infect the lens.Experimental infection of pregnantrats and hamsters with human rubellavirLus resulted in a wide range of con-genital anomalies, inCluding cataracts,.imong the offspring.One of the nmost inmportant consid-

erations in the analysis of the cellpopLIlation dynamics of the vertebratelens is the factor, or complex of fac-tors. which controls imiitotic activityin the epitheliumII of this structure.TWo of the papers in the last sessionol' the conference directed attentionto this aspect of lens development.Nancy Rafferty (Johns Hopkins Uni-versity) reported on injury-associatedchanges in the epitheliumLII of thefrog lens. This investigator confirmed herear-lier findings that injiurv to the epithe-Iumliu results in a niarked increase in itsproliferative rate. Studies of' cell densitywere couLpled with autoradiography ofthree regions at diflTe-eret distancesfrom] the center of the epitheliuLm. B)studying changes in these three re-gions as ta fuLnction of timie followinginjuLry to the center of the lens epi-thelium]I it was possible to show thatinjulry to the epitheliurm shortens theG., fromii 6 Ihours to 21 "2 or 3hours. DNA synthesis and the ensuingcell divisions begin in the cells of theproliferative zone near the equLator fol-low ing inLjurL-y to the center- of theepitheliu111m. DNA synthetic activityand mitosis sweep centrallNy towxard theWvoUnd as time elapses. This observa-tion indicates either that the stimu-lated cells of the proliferative zoneaIctuLally, migr-ate toward the wouLnd astheyr continue to proliferate, or elsethat the injLryvstimullus proceeds fronmthe proliferative zone toward thexxound, stimnulating new cells along the\\ ax to divide.

C'lifl'ord Harding. W. L. Wilson, andJean Wilson (Oakland University) alsoconsidered the control of mitosis in thelens epithelium. They have demon-<.trated a large and rapid increase inmitotic activity in explanted lenses ofthe rabbit which are exposed to serum.This increase in mitotic activity is pre-ceded by a latent period. Dialysis of theserunm yielded two fractions, neitherof which was capable of stimulatingmitotic activity in the epithelium ofthe rabbit lens. Recombining these

SCIENCE, VOL. 1541 686

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23-25. Aerospace Science, 5th mtg.,American Inst. of Aeronautics and Astro-nautics, New York, N.Y. (Manager ofPublic Information, AIAA, 1290 SixthAve., New York 10019}

23-25. Society of Thoracic Surgeons,mtg., Kansas City, Mo. (F. X. Byron, TheSociety, City of Hope Medical Center,1500 E. Duarte Rd., Duarte, Calif. 91010)23-27. Relativistic Astrophysics, symp.,

New York, N.Y. (A. G. W. Cameron,Belfer Graduate School of Science, Ye-shiva Univ., New York 10033)

24-27. Comparative Pharmacology, in-tern. symp., Natl. Inst. of Health, Bethes-da, Md. (G. J. Cosmides, Room 5B29,Bldg. 31, NIH, Bethesda 20014)

25-27. American Crystallographic As-soc., mtg., Georgia Inst. of Technology,Atlanta. (W. L. Kehl, Gulf Research andDevelopment Co., P.O. Drawer 2038,Pittsburgh, Pa. 15230)

25-27. American Mathematical Soc.,73rd annual mtg., Houston, Tex. (TheSociety, P.O. Box 6248, Providence, R.I.)

25-28. American Group PsychotherapyAssoc., New York, N.Y. (Mrs. M. Schiff,1790 Broadway, New York 10019)26-28. Mathematical Assoc. of Amer-

ica, 50th annual mtg., Houston, Tex. (H.L. Alder, Univ. of California, Davis)

28-30. Radiology, southern conf., PointCAear, Ala. (M. Eskridge, P.O. Box4097, Mobile, Ala.)

28-1. American Acad. of Allergy,Phoenix, Ariz. (J. 0. Kelley, 756 NorthMilwaukee St., Milwaukee, Wis. 53202)

29. Mossbauer Effect Methodology, 3rdannual symp., New York, N.Y. (P. A.McNulty, New England Nuclear Corp.,575 Albany St., Boston, Mass. 02118)

29-3. Power, mtg., Power Group, Inst.of Electrical and Electronics Engineers,New York, N.Y. (E. C. Day, IEEE, 345E. 47 St., New York 10017 )

30. American Soc. of Heating, Refrig-erating, and Air Conditioning Engineers,semi-annual mtg., Detroit, Mich. (MissJ. I. Szabo, 345 E. 47 St., New York10017)

30-1. Personnel Radiation Dosimetry,symp., Chicago, Ill. (J. H. Pingel, Ar-gonne Nat]. Laboratory, Bldg. 301, 9700S. Cass Ave., Argonne, Ill. 60439)

30-2. American Physical Soc., annualmtg., New York, N.Y. (The Society, Ex-ecutive Secretary, Columbia Univ., NewYork 10027)

30-2. American Assoc. of PhysicsTeachers, New York, N.Y. (A. B. Arons,Physics Dept., Amherst College, Amherst,Mass.)

30-3. Zodiacal Light and the Inter-planetary Medium, intern. symp., Hono-lulu, Hawaii. (F. E. Roach, AeronomyLab., Inst. for Telecommunication Sci-ences and Aeronomy, Environmental Sci-ence Services Administration, Boulder,Colo. 80302)

31-2. Ciba Foundation symp. on CellDifferentiation, London, England. (Ciba,41 Portland P1., London W.1)

31-3. Reinforced Plastics, 22nd conf.,Soc. of the Plastics Industry, Washington,D.C. (The Society, 250 Park Ave., NewYork 10017)

31-4. American College of Radiology,mtg., Los Angeles, Calif. (American Col-lege of Radiology, 20 N. Wacker Dr.,Chicago, Ill.)

SCIENCE, VOL. 154

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