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HEALTH SCIENCES LIBRARYtM.cMASTER UNIVERSITY

DEC 2 9 75

19 December 1975

SC Volume 190, No. 4220

AMERICANA SSOCITION IPOR T ADVAET O- SCIENCE

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SOYOU RATE ANULTRORAC !

A little envy is pardonable. Not everyone is lucky enough to havethe finest fraction collector in the world.But if your work calls for precision and reliability in electronically-controlled fraction collecting, you need an UltroRacS, too.

LKB Instruments Inc.12221 Parklawn Drive, Rockville MD. 2085211744 Wilshire Blvd. Los Angeles Calif. 900256600 West Irving Park Road, Chicago 1II. 60634260 North Broadway, Hicksville N.Y. 118013700 Chapel Hill Blvd., Durham, N.C. 27707

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~~~~~~~~~~~crlNo 61 on Reaer Seric cord

ia 0. i.X

THE STRUGGLE FOR SURVIVAL

climate and global survival

The Genesis StrategyStephen H. SchneiderNational Center for Atmospheric Research

With Lynne E. MesirowDirectly confronts the impact of climate fluc-tuation on world agriculture and food supplies.Critics hail this vital book"This brilliant book by a young, concernedscientist is just what the world needs ... Acombination of responsible climatology, cit-izen concern, and relevance to the needs ofthe people of the world. Relevant, timely, es-sential... buttressed with facts - but not toomany for the layman to digest as preparationfor action." -Margaret Mead

". . . one of the most crucial factors in thehuman predicament . .. written by one of theworld's most competent climatologists . . . It isa must for all those interested in what thefuture holds." Paul Ehrlich

navigates skilfully between Cassandraand Pollyanna . . . he doesn't hide behind theobscurities of scientific language but writesabout the problems that touch us all in plainEnglish we can-and had better-understand.

-Harlan Cleveland

$12.95

crucial to us all

Food for LifeF. E. DeatherageOhio State UniversityThis book clarifies the issues involved in theone problem that is crucial to us all -food.A fundamental text for students and profes-sionals alike, it defines the interacting princi-ples of the biological, physical, and socialsciences that determine how food is produced,processed, distributed, and consumed. Everyaspect of food is covered, from the inceptionof the single cell to the challenge of feedingan ever-increasing population. $19.50

the harmful and healing effects

Living With Our Sun's UltravioletRaysArthur C. GieseStanford UniversityDoes overexposure to the sun cause skincancer? Will aerosols tear away our ozoneshield? This contemporary text explores thesequestions and describes how life has evolvedto adopt to the ultraviolet "load" from the sunby continuous repair of radiation damage.Focusing on ultraviolet photobiology, the au-thor details the factors that most upset thedelicate balance between damage and repair:

* reduction of the ozone layer by strato-spheric pollution

* natural dyes, medications, and pollutantswhich absorb light and pass its energyto sensitive chemicals in the cell

* the absence of radiation repair mech-anisms in mutant cells.

$19.50

the last work of an eminent physiologistElements in Living SystemsHenry A. SchroederWith a foreword by H. B. Perry, Jr.

While all things are made up of a combinationof elements, some are essential for life, somehave specialized functions, and some interferewith life itself. Examining the elemental com-position of living things-especially humans-this work describes the functions of the traceelements in living systems. Presenting a re-view of the literature to date, the book analyz-es the effect of environmental pollution on thefood chain and explores resulting reconditetoxicity that can be linked to human disease.Including data essential to public healthstudies, this work has many implications forresearch in immunology, chronic disease, andcancer. $35.00

PLENUM PUBLISHING CORPORATION, 227 West 17th Street, New York, N.Y. 10011In United Kingdom: 8 Scrubs Lane, Harlesden, London NW10 6SE, EnglandPrices subject to change without notice. Prices slightly higher outside the U.S.

ENN%bl

19 DECEMBER 1975 Circle No. 387 on Readers' Service Card 1143

Also new from HP: The HP 9871 Page-widthPrinter/Plotter. Its unique bi-directionalplaten and96-character printing disk let you run program-formulated charts and graphs; tables and text.Works with all HP 9800 seriescomputing calculators.

Announcing the HP9815.Lookwhat your

bucks will buy now.High-speed data cartridgeprovides up to 96,384 bytesof program and data storage.Dual-track, 140 foot mag-netic tape can be searchedbi-directionally at 60 inchesa second.Thermal printer has full setof alphanumeric characters.Prints up to 16 charactersper line at 2.8 lines a second.

Easy-on-the-eyes displaycan display up to 16 numericcharacters or up to 10 digitsin scientific notation.

15 user definable keysallow single keystrokeexecution of programmedroutines.

Auto-Start switch initializesprograms so an operatorneed only switch on thepower and Auto-Start, andbegin interacting with pro-grams. It also provides power-fail restart. \

Simplified programming,based on easy-to-understandlogic and easy-to-remembermnemonics, lets you writepowerful, complex programseasily. / /

Powerful editing featuresallow you to modify and up-date programs quickly andaccurately.Built-in math and trigfunctions provide simple,convenient keystroke calcula-tions-just like you get fromHP hand-held calculators.HP stack-oriented nota-tion is the efficient, powerfulmethod for arithmetic opera-tions. It reduces equations toa few easily-handled steps.Compact and portable,the 13 pound HP 9815 isjust 13Y2" x 131/2" x 4".*U.S. domestic price only. Does notindude options, programs or peripherals.

And that's just for starters.At its base-price, the new HP 9815 computing calculator is

a price/performance leader. And the powerful 9815 becomes a uniquely versatileperformer as you add optional features.

Interfacing capability is provided through an optional $200* two-channel I/O module.It allows a choice of seven different HP peripherals to work with the 9815,

including the new 9871 page printer. You just plug them in, and they're ready to go.HP interface cards and cables allow the 9815 to control, gather and process data

from a variety of instruments. And by adding an HP-Interface Bus,up to 14 instruments can be monitored simultaneously.

HP general-purpose programs are now available for statistics,electrical engineering design, surveying and radioimmunoassay. With them, problem

solving is reduced to data entry.Power, versatility, simplicity, low-cost-these are the characteristics of

the new 9815. We call it a four-dimensional machine. Call your local HP sales office,or write for a copy of the HP 9815 brochure, and you'll see why.

HP computing calculators put the power where the problems are.

HEWLETT J PACKARD

Sales and service from 172 offices in 65 countries.P 0 Box 301 Loveland. Colorado 80537

Circle No. 455 on Readers' Service Card

095il7

SCIENCE, VOL. 190 1147

1Iways to order

Eastman Organic Chemicals

from somebody else.

Contact any one of these 81 dealers who stock EastmanOrganic Chemicals. With nearby branches, they can giveyour order fast delivery, close attention, and personalizedservice.

For quotes on bulk or specialty chemicals, contact your82nd source: Eastman Organic Chemicals, EastmanKodak Company, Rochester, N.Y. 14650. Phone (716)458-4080.

Orders may be placed with any of the following distributor locations:

ALABAMASargent-Welch Scientific Co.3125 7th Avenue NorthBirmingham, AL 35201Area (205) 251-5125

CALIFORNIABeckman Instruments, Inc.Science Essentials OperationP.O. Box 61001550 South State College Blvd.Anaheim, CA 29806Area (714) 639-8781Curtin Matheson Scientific Company, Inc.P.O. Box 386470 Valley DriveBrisbane, CA 94005Area (415) 467-1040Curtin Matheson Scientific Company, Inc.P.O. Box 853718095 Mt. ShayFountain Valley, CA 92708Area (714) 556-7010Fisher Scientific Co.17921 Sky ParkIrvine, CA 92707Area (714) 546-4432Fisher Scientific Co.2225 Martin Ave. #KSanta Clara, CA 95050Area (408) 244-0660Sargent-Welch Scientific Co.1617 East Ball RoadAnaheim, CA 92803Area (714) 772-3550SciChem Co.Frese Division1430 Grande Vista AvenueLos Angeles, CA 90023Area (213) 263-7151

COLORADOSargent-Welch Scientific Co.4040 Dahlia StreetDenver, CO 80207Area (303) 399-8220

CONNECTICUTBrand-Nu Laboratories30 Maynard StreetMeriden, CT 06450Area (203) 235-7989

FLORIDACurtin Matheson Scientific Company, Inc.7524 Currency DriveOrlando, FL 32809Area (305) 859-8281

1148

Fisher Scientific Co.7464 Chancellor DriveOrlando, FL 32809Area (305) 633-9861

GEORGIACurtin Matheson Scientific Company, Inc.P.O. Box 435285800 Bucknell Drive S.W.Atlanta, GA 30336Area (404) 349-3710Fisher Scientific Co.2775 Pacific DriveNorcross, GA 30071Area (404) 449-5050VWR ScientificP.O. Box 20158890 Chattahoochee Avenue N.W.Atlanta, GA 30325Area (404) 351-3872

HAWAIICurtin Matheson Scientific Company, Inc.P.O. Box 5308Honolulu, HI 96814Area (808) 988-2111

ILLINOISCurtin Matheson Scientic Company, Inc.1850 Greenleaf AvenueElk Grove Village, IL 60007Area (312) 439-5880Fisher Scientific Co.1458 North Lamon AvenueChicago, IL 60651Area (312) 379-9300Stansi Scientific DivisionFisher Scientific Co.1259 North Wood StreetChicago, IL 60622Area (312) 772-3100Sargent-Welch Scientific Co.7300 North Linden AvenueSkokie, IL 60076Area (312) 677-0600

KENTUCKYPreiser Scientific, Inc.1500 Algonquin ParkwayLouisville, KY 40201Area (502) 636-3307

LOUISIANACurtin Matheson Scientific Company, Inc.P.O. Box 53387621 Celeste StreetNew Orleans, LA 70153Area (504) 524-0475

MARYLANDBeckman Instruments, Inc.Science Essentials Operation11961 Tech RoadSilver Spring, MD 20904Area (301) 622-2500Curtin Matheson Scientific Company, Inc.10727 Tucker StreetBeltsville, MD 20705Area (301) 937-5950Fisher Scientific Co.7722 Fenton StreetSilver Spring, MD 20910Area (301) 587-7000North-Strong, Inc.7322 Westmore RoadRockville, MD 20850Area (301) 762-2121

Preiser Scientific, Inc.4720 Montgomery LaneBethesda, MD 20014Area (301) 340-7882VWR ScientificP.O. Box 86036601 Amberton DriveBaltimore, MD 21227Area (301) 796-8500

MASSACHUSETTSCurtin Matheson Scientific Company, Inc.100 Commerce Way-Bldg. #1Woburn, MA 01801Area (617) 935-8888Fisher Scientific Co.461 Riverside AvenueMedford, MA 02155Area (617) 391-6110SciChem Co.45 William StreetEverett, MA 02149Area (617) 389-7000VWR ScientificP.O. Box 232Boston, MA 02101Area (617) 969-0900

MICHIGANCurtin Matheson Scientific Company, Inc.1600 Howard StreetDetroit, MI 48216Area (313) 965-6422Curtin Matheson Scientific Company, Inc.P.O. Box 12282400 James Savage RoadMidland, MI 48640Area (517) 631-9500

SCIENCE, VOl 190

Fisher Scientific Co.34401 Industrial RoadLivonia, MI 48150Area (313) 261-3320Sargent-Welch Scientific Co.8560 West Chicago AvenueDetroit, MI 48204Area (313) 931-0337

MINNESOTACurtin Matheson Scientific Company, Inc.2218 University Avenue S.E.Minneapolis, MN 55414Area (612) 378-1110

MISSOURICurtin Matheson Scientific Company, Inc.P.O. Box 3433 160 Terrace StreetKansas City, MO 64141Area (816) 561-8780Curtin Matheson Scientific Company, Inc.P.O. Box 149411526 Adie RoadMaryland Heights, MO 63043Area (314) 872-8100Fisher Scientific Co.1241 Ambassador BoulevardSt. Louis, MO 63132Area (314) 991-2400

NEW JERSEYBeckman Instruments, Inc.Science Essentials OperationU.S. Highway 22 at Summit RoadMountainside, NJ 07091Area (201) 232-7600Curtin Matheson Scientific Company, Inc.Mid-Atlantic Industrial Park1571 Imperial WayThorofare, NJ 08086Area (609) 848-1500 & (215) 462-4700Curtin Matheson Scientific Company, Inc.357 Hamburg TurnpikeWayne, NJ 07470Area (201) 278-3300Fisher Scientific Co.1 Reagent LaneFair Lawn, NJ 07410Area (201) 796-7100Fisher Scientific Co.52 Fadem RoadSpringfield, NJ 07081Area (201) 379-1400Sargent-Welch Scientific Co.35 Stern AvenueSpringfield, NJ 07081Area (201) 376-7050

NEW YORKBioclinical Laboratories375 Central AvenueBohemia, NY 11716Area (516) 567-6677Fisher Scientific Co.15 Jet View DriveRochester, NY 14624Area (716) 464-8900VWR ScientificP.O. Box 23Bronx, NY 10452Area (212) 294-3000VWR ScientificP.O. Box 105039 Russell StreetRochester, NY 14603Area (716) 288-5881VWR ScientificP.O. Box 1821130 Military RoadBuffalo, NY 14240Area (716) 874-3072

19 DECEMBER 1975

NORTH CAROLINAFisher Scientific Co.3315 Winton RoadRaleigh, NC 27604Area (919) 876-2351Preiser Scientific, Inc.804 North Miami BoulevardDurham, NC 27703Area (919) 688-5583SciChem Co.2400 East Pettigrew StreetDurham, NC 27702Area (919) 596-1341

OHIOCurtin Matheson Scientific Company, Inc.12101 Centron PlaceCincinnati, OH 45246Area (513) 671-1200Curtin Matheson Scientific Company, Inc.4540 Willow ParkwayCleveland, OH 44125Area (216) 883-2424Fisher Scientific Co.5481 Creek RoadCincinnati, OH 45242Area (513) 793-5100Fisher Scientific Co.26401 Miles AvenueWarrensville HeightsCleveland, OH 44128Area (216) 292-7900Sargent-Welch Scientific Co.10400 Taconic TerraceCincinnati, OH 45215Area (513) 771-3850Sargent-Welch Scientific Co.9520 Midwest AvenueGarfield HeightsCleveland, OH 44125Area (216) 587-3300VWR ScientificP.O. Box 8552042 Camero AvenueColumbus, OH 43215Area (614) 445-8281

OKLAHOMACurtin Matheson Scientific Company, Inc.Box 747Tulsa, OK 74101Area (918) 622-1700

PENNSYLVANIAFisher Scientific Co.191 South Gulph RoadKing of Prussia, PA 19406Area (215) 265-0300Fisher Scientific Co.711 Forbes AvenuePittsburgh, PA 15219Area (412) 562-8300

TENNESSEEPreiser Scientific, Inc.CSI Building2162 Courtland PlaceMemphis, TN 38104Area (901) 276-6112

Curtin Matheson Scientific Company, Inc.P.O. Box 15464220 Jefferson AvenueHouston, TX 77001Area (713) 923-1661Fisher Scientific Co.10700 Rockley RoadHouston, TX 77072Area (713) 523-6605GAC LaboratoriesP.O. Box 29641San Antonio, TX 78229Area (512) 684-2797Sargent-Welch Scientific Co.5915 Peeler StreetDallas, TX 75325Area (214) 357-9381

WEST VIRGINIAPreiser Scientific, Inc.900 MacCorkle Avenue S.W.Charleston, WV 25322Area (304) 343-5515Preiser Scientific, Inc.Jones & Oliver StreetsSt. Alban, WV 25177Area (304) 727-2902

WISCONSINCurtin Matheson Scientific Company, Inc.1429 Wentker CourtTwo Rivers, WI 54241Area (414) 793-2269

CANADAFisher Scientific Co., LimitedBox 3840-Station DEdmonton, Alberta TSL 4K1Area (403) 455-3151Fisher Scientific Co., Limited194 West Third AvenueVancouver 10, B.C.Area (604) 872-7641Fisher Scientific Co., Limited184 Railside RoadDon Mills, Ontario M3A 1A9Area (416) 445-2121Fisher Scientific Co., Limited1830 Walkley-Station EOttawa, Ontario KlS 5A9Area (613) 731-0470Fisher Scientific Co., Limited8555 Devonshire RoadMontreal 9, QuebecArea (514) 735-2621Fisher Scientific Co., Limited21 Gurholt DriveDartmouth Industrial ParkDartmouth, Nova ScotiaArea (902) 469-9891

Sargent-Welch Scientific of Canada, Ltd.285 Garyray DriveWeston, OntarioArea (416) 741-5210

TEXASBeckman Industries, Inc.Science Essentials Operation5810 Hillcroft Ave.Houston, TX 77036Area (713) 781-0810Curtin Matheson Scientific Company, Inc.P.O. Box 53041103-07 Slocum StreetDallas, TX 75222Area (214) 747-2503

1149

Announcing:

Now your J.L.Baker distributorcan

also ship you things he doesn't have!

How can your Baker distributor ship you things he doesn't have? Easy. Henow can immediately contact the Baker Super Service Center and-in almost every instance-have the desired item shipped directly to youwithin 24 hours. It's as though your J. T. Baker distributor has just added thelargest reagent warehouse in the world to his backyard to serve you. (Tosuper-serve you.)

Now depend on your nearest Baker distributor for all of your laboratoryreagent needs. He's listed on the facing page.

And do you have our new 428-page Catalog 750 featuring thousands of Bakerquality laboratory chemicals? If not, please use coupon below. Thanks.

J. T. Baker Chemical Co.1 222 Red School Lane

Phillipsburg, N.J. 08865

Please forward a copy of your new Catalog 750.

Name

Title

Dept. |

OrganizationAddress

___________________________Zip

1150

Check Baker first!

JITBakerJ. T. Baker Chemical Co.222 Red School Lane

Phillipsburg, N.J. 08865201 /859-5411

Circle No. 591 otn Readers' Service Card

JI Baker

DISTRIBUTORSALABAMASargent-Welch Scientific Co.Birmingham205 / 251-5125

ARIZONAVWR ScientificPhoenix602 / 272-3272VWR ScientificTucson602 / 624-8371

CALIFORNIASargent-Welch Scientific Co.Anaheim714 / 772-3550VWR ScientificLos Angeles213 / 265-8123VWR ScientificSan Diego714 / 262-0711VWR ScientificSan Francisco415 / 469-0100Curtin-Matheson Scientific Co.Brisbane415 / 467-1040Curtin-Matheson Scientific Co.Fountain Valley714 / 963-6761

COLORADOVWR ScientificDenver303 / 388-5651Sargent-Welch Scientific Co.Denver303 / 399-8220

CONNECTICUTBrand-Nu Laboratories, Inc.Meriden203 / 235-7989

DELAWAREJohn G. Merkel & SonsWilmington302 / 654-8818

FLORIDACurtin-Matheson Scientific Co.Orlando305 / 859-8281

GEORGIACurtin-Matheson Scientific Co.Atlanta404 / 349-3710VWR ScientificAtlanta404 / 351-3872Estes Surgical Supply Co.Atlanta404 / 521-1700

HAWAIIVWR ScientificHonolulu808 / 847-1361

ILLINOISSargent-Welch Scientific Co.Skokie312 / 267-5300A. Daigger & Co.Chicago312 / 644-9438LaPine Scientific Co.Chicago312 / 735-4700

Macmillan Science Co., Inc.Chicago312 / 488-4100SGA Scientific Inc.Elk Grove Village312 / 439-2500Technical Industrial ProductsEast Peoria309 / 694-6226Wilkens-Anderson Co.Chicago312 / 384-4433Curtin-Matheson Scientific Co.Elk Grove Village312 / 439-5880Rascher & Betzold, Inc.Chicago312 / 275-7300

INDIANAGeneral Medical of IndianaIndianapolis317 / 634-8560

KENTUCKYPreiser Scientific Inc.Louisville304 / 343-5515

LOUISIANACurtin-Matheson Scientific Co.New Orleans504 / 524-0475

MARYLANDCurtin-Matheson Scientific Co.Beltsville301 / 937-5950VWR ScientificBaltimore301 / 796-8500

MASSACH USETTSDoe & Ingalls, Inc.Medford617 / 391-0090Curtin-Matheson Scientific Co.Woburn617 / 935-8888Healthco ScientificCanton617 / 828-3310SciChemCoEverett617 / 389-7000VWR ScientificNewton Upper Falls617 / 969-0900

MICHIGANCurtin-Matheson Scientific Co.Detroit313 / 964-0310Curtin-Matheson Scientific Co.Midland517 / 631-9500Rupp & Bowman CompanyDetroit313 / 491-7000Sargent-Welch Scientific Co.Detroit313 / 931-0337

MINNESOTACurtin-Matheson Scientific Co.Minneapolis612 / 378-1110Hawkins Chemical Co.Minneapolis612 / 331-6910Lerlab Supply Co.Hibbing218 / 262-3456Physicians & Hosp. Supply Co.Scientific & Laboratory Div.Minneapolis612 / 333-5251

MISSOURICurtin-Matheson Scientific Co.Kansas City816 / 561-8780Curtin-Matheson Scientific Co.Maryland Heights314 / 872-8100

MONTANANorthwest Scientific Co.Billings406 / 252-3269

NEW JERSEYAce Scientific Supply Co., Inc.Linden201 / 925-3300Amend Drug & Chem. Co., Inc.I rvington201 926-0333212/ 228-8920J. & H. Berge, Inc.South Plainfield201 / 561-1234Beckman Instruments Inc.Mountainside201 / 232-7600Curtin-Matheson Scientific Co.Wayne201 / 278-3300Macalaster Bicknell of N.J., Inc.Miliville609 / 825-3222Sargent-Welch Scientific Co.Springfield201 / 376-7050SGA Scientific Inc.Bloomfield201 / 748-6600212 / 267-9451Seidler Chem. & Supply Co.Newark201 / 622-4495

NEW MEXICOVWR ScientificAlbuquerque505 / 842-8650

NEW YORKAlbany Laboratories, Inc.Albany518 / 434-1747Ashland Chemical Co.Binghamton607 / 723-5455Berg Chemical Co.New York212 / 563-2684Kem ChemicalMt. Vernon914 / 699-3110New York Lab. Supply Co.West Hempstead516 / 538-7790Riverside Chemical Co.N. Tonawanda716 / 692-1350VWR ScientificRochester716 / 288-5881

NORTH CAROLINACarolina Biological Supply Co.Burlington919 / 584-0381

OHIOCurtin-Matheson Scientific Co.Cincinnati513 / 671-1200Curtin-Matheson Scientific Co.Cleveland216 / 883-2424VWR ScientificColumbus614 / 445-8281Sargent-Welch Scientific Co.Cincinnati513 / 771-3850Sargent-Welch Scientific Co.Garfield Heights, Cleveland216 / 587-3300

OKLAHOMACurtin-Matheson Scientific Co.Tulsa918 / 622-1700Melton Company, Inc.Labco Scientific Div.Oklahoma City405 / 235-3526

OREGONVWR ScientificPortland503 / 225-0400

PENNSYLVANIAArthur H. Thomas CompanyPhiladelphia215 / 627-5600

Bellevue Surgical Supply Co.Reading215 / 376-2991Bowman-Mell Co., Inc.Harrisburg717 / 238-5235

Dolbey ScientificPhiladelphia215 / 748-8600Para Scientific Co.Fairless Hills609 / 882-4545Reading Scientific Co.Reading215 / 921-0221Scientific Equipment Co.Philadelphia215 / 222-5655

RHODE ISLANDEastern Scientific Co.Providence401 / 831-4100

TENNESSEEDurr-Fillauer SurgicalSupplies, Inc.Chattanooga615 / 267-1161Nashville Surgical Supply Co.Nashville615 / 255-4601

TEXASCurtin-Matheson Scientific Co.Dallas214 / 747-2503Curtin-Matheson Scientific Co.Houston713 / 923-1661Sargent-Welch Scientific Co.Dallas214 / 357-9381Capitol ScientificAustin512 / 836-1167VWR ScientificHouston713 / 641-0681VWR ScientificEl Paso915 / 778-4225

UTAHVWR ScientificSalt Lake City801 / 328-1112

VIRGINIAGeneral MedicalVienna703 / 938-3500General ScientificRichmond804 / 264-2861

WEST VIRGINIAPreiser ScientificCharleston304 / 343-5515

WASH INGTONVWR ScientificSeattle206 / 447-5811

WISCONSINGenetec Hospital Supply Co.Div. of McKesson & RobbinsMilwaukee414 / 271-0468Drake BrothersMenomonee Falls414 / 781-2166

JIBa r

Nikon is helping

prevent the

fatal embolism.Most potential heart patients are unaware of the insidious develop-ment of thrombosis. The first realization often follows a debilitatingattack. Or, at best, some other early warning signal.What aberrations contribute to the formation of emboli? How can

they be controlled? And, better still, prevented? A renowned pathol-ogist in the San Francisco area is deeply involved in answeringthese and many similar questions.

"An important tool in his research is the Nikon Multiphot Univer-sal Photographic Stand," reports Chuck Berger, EPOI District Man-ager. The physician routinely uses the Multiphot to produce 35mmtransparencies of emboli in freshly prepared artery sections. Theslides are used in lectures, and for reproduction in research papers.

This significant research is directed toward a better understand-ing of the mechanism of thrombosis, and development of therapywhich may safely be used in the prevention of thromboembolism.The Nikon Multiphot was selected because of its "versatility and

optical excellence," says Berger. In 35mm work, adapters are avail-able for Nikon F, F2 and Nikkormat camera bodies. Four speciallydesigned Macro Nikkor lenses produce extremely sharp imageswith a magnification range from 1 /3X to 40X.The instrument is designed with double support columns for rock-

steady photographic work. It can be used for transmitted as well asreflected light formats up to 4" x 5". And a superbly designeddiascopic transilluminating base assembly with special condensersassures even illumination of transparent specimens.

Write for details on this fine research instrument. Nikon Inc., In-strument Group, Ehrenreich Photo-Optical Industries, 623 StewartAvenue, Garden City, New York 11530. Telephone (516) 248-5200.Nikon is involved.

If~ Nikon Inc., InstrumentGroup, Ehrenreich Photo-Optical Industries, (M/on)623 Stewart Avenue, Garden City, New York 11530.

- L Please have a local Nikon representative contact me.

Please send detailed information on:_E Nikon Multiphot, Universal Photographic Stand For 35mm, 4x5, and

II. Polaroid photomacrography.E Nikon CFMA Automatic attachment with intervalometer, motor drive,

and automatic exposure control for fully automatic time-lapse cine-EFM, micrography.

O Nikon PFM, EFM, AFM Standard prism, semi-automatic, and fullyautomatic Microflex attachments for a wide range of photomicrographicapplications.New forty-two page Nikon microscope catalog.

NameAffiI iationAddress-City -

Title

-State- -ZipeirIcle No. 532 on Readers' Service Cardc-

PFM,

Nikon Multiphot Nikon CFMA AFMS-12-19-75

V%."m4,F,--ow

IW. 0

gilk

uwt"0er metX0ranoos are easity re-solvedand their exact Jocationsplotted. Any size centrifuge tubecan be quantitatively scanned attwo wavelengths and fraction-ated vwith or without piercing.The Model 570 gradient

former sequentially produces up

to 22 absolutely identical linearor curved gradients of any sizefrom 3 to 80 ml. Gradient sizeand shape are precisely and re-

producibly determined by dif-ferential pumping.

In addition to these instru-ments, our general catalogdescribes gradient pumps andscanners for zonal rotors, plusinstrumentation for liquidchromatography and electro-phoresis. Send for your copy

now.

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West by certain circles interested in the frustra-tion of the relaxation of international tensionand in the revival of the cold war, and in seekingpretexts to defame-by any means-the nobleaims and sincerity of the Soviet foreign policythat has gained unanimous gratitude and popu-larity throughout the world.The decision of the Nobel committee to con-

fer the peace prize on Sakharov-a decision thatfundamentally contradicts the spirit and the let-ter of the basic provisions relating to thisprize-is unacceptable to genuine champions ofpeace. Soviet scientists believe that the award ofthe Nobel prize to Sakharov is unworthy andprovocative, and is a blasphemy against thenoble ideas-dear to all of us-of humanism,peace, justice, and friendship among the peoplesof all countries.[Signed by] G. B. Abdullaev, G. A. Avsyuk,A. P. Aleksandrov, V. A. Ambartsumyan,M. S. Asimov, A. A. Baev, N. G. Basov, N. V.Belov, N. A. Borisevich, A. E. Braunshtein,A. P. Vanichev, 1. N. Vekua, E. P. Velikhov,A. P. Vinogradov, S. 1. Vol'fkovich, S. V.Vonsovskii, B. M. Vul, Ya. S. Grosul, N. P.Dubinin, N. M. Zhavoronkov, Yu. A. Zhdanov,A. A. Imshenetskii, A. Yu. Ishlinskii, A. P.Kapitsa, K. K. Karakeev, M. V. Keldysh, F. V.Konstantinov, V. A. Kotel'nikov, E. M. Kreps,A. M. Kunaev, G. V. Kurdyumov, A. L. Kur-sanov, M. A. Lavrent'ev, L. M. Leonov, A. A.Logunov, A. K. Malmeister, M. A. Markov,G. 1. Marchuk, Yu. Yu. Matulis, N. V.Mel'nikov, 1. 1. Mints, E. N. Mishustin, A. N.Nesmeyanov, A. 1. Oparin, B. E. Paton, B. N.Petrov, N. A. Pilyugin, B. B. Piotrovskii, P. N.Pospelov, A. M. Prokhorov, 0. A. Reutov,A. M. Rumyantsev, K. M. Ryzhikov, B. A.Rybakov, A. S. Sadykov, N. N. Semenov, D. V.Skobel'tsyn, G. K. Skryabin, V. 1. Smirnov,V. 1. Spitsyn, V. D. Timakov, A. N. Tikhonov,A. A. Trofimuk, V. M. Tuchkevich, P. N.Fedoseev, N. P. Fedorenko, G. N. Flerov,A. V. Fokin, A. N. Frumkin, M. B. Khrap-chenko, N. V. Tsitsin, V. A. Engel'gardt.

IRVING S. BENGELSDORFDivision ofHumanities and SocialSciences, California Institute ofTechnology, Pasadena 91125

Notes

1. The nine academicians whose signatures appearedunder the 1973 Pravda letter, but not under the1975 Izvessiya letter, are N. N. Bogolyubov, B. M.Kedrov, A. M. Obukhov, Yu. A. Ovchinnikov, L.1. Sedov, S. L. Sobelev, 1. M. Frank, Yu. B. Khari-ton, and P. A. Cherenkov.

Wood Versus Fossil Fuel forExcess Carbon Dioxide

Erik P. Eckholm's recent estimate, re-ported by Constance Holden (News andComment, 3 Oct., p. 36), that "one-third ofthe world's population depends on woodfor cooking (and, to a lesser extent, heat-ing)" has interesting ramifications for de-tailed interpretations of the carbon dioxidebuildup in the atmosphere in the past cen-tury. It has been estimated that half of thewood harvested each year is burned.

Lundell (1) has reviewed the box modelsof the carbon cycle proposed by Craig (2),Bolin (3), and others. Lundell has also cal-

Circle No. 555 on Readers' Service Card

culated the boundary conditions for theshifting of exchange rates among the vari-ous carbon dioxide reservoirs. Wood-burn-ing and deforestation have two additive ef-fects. Wood-burning releases a largeamount of carbon dioxide into the atmo-sphere, perhaps much more than has beenpreviously estimated (for example, the esti-mate that 1.1 metric tons of wood areburned per capita per year in Thailand).Deforestation for lumber (and urban-ization) has the additive effect of destroy-ing the photosynthesizing organisms thattransfer atmospheric carbon dioxide backinto what we now propose as the "cellulosereservoir." The inflow and outflow into thecellulose reservoir during the last centuryis difficult to estimate, but a key andsimple question is, Why hasn't photosyn-thesis prevented the 15 percent or so in-crease in atmospheric carbon dioxide inthe last century? The current shortage offirewood suggests that part of the answerlies in a rapidly expanding human popu-lation burning cellulose much faster than itis being formed and held in living trees.Radiocarbon studies have documented theeffects on the atmosphere of burning fossilfuel, but the wood-burning contribution tothe atmospheric excess of carbon dioxide ismore difficult to document because the cel-lulose reservoir has a radiocarbon/carbonratio only a few percent different from thatof the atmosphere.

It is possible that the biosphere could re-store the cellulose reservoir in some dec-ades, but only if the remaining parts of thereservoir (for example, the Amazon forest)are not depleted, if the population and percapita annual consumption are stabilized,and if, as Eckholm suggests, even more re-forestation is undertaken.

J. A. S. ADAMSDepartment ofGeology, RiceUniversity, Houston, Texas 77001

L. L. LUNDELLDepartment ofGeology, University ofWyoming, Laramie 82070

M. S. M. MANTOVANIInstituto Astronomico e Geofisico,Universidade de Sdo Paulo, Caixa PostalNo. 30.627, Sao Paulo, S.P., Brazil

References

1. L. L. Lundell, thesis, Rice University (1973).2. H. Craig, Tellu.s 9, 1 (1957).3. B. Bolin, Sci. Am. 233, 124 (September 1970).

Sex Differentials in Academic Salaries

In Bayer and Astin's article (23 May,p. 796), the section dealing with salariescontains an error that vitiates a large partof their analysis. In August 1974 one of

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my students, Susan M. Speer, and I issueda press release about 1972-73 salary differ-entials (1) based on the same data as thoseused by Bayer and Astin data from thefaculty survey carried out by the AmericanCouncil on Education. When we began ouranalysis we noticed immediately an unusu-al marginal distribution for the data onfaculty salaries: implausibly large numbersof respondents were shown to have "cur-rent base institutional salary" on the orderof $70,000, $80,000 or $90,000. On in-specting the questionnaire we found thatrespondents had been asked to round theirsalaries to the nearest $1000 by marking anumber in each of two columns of num-bers. We hypothesized that a significantproportion of respondents who receivedsalaries of less than $10,000 had inadver-tently rounded to the nearest $100. In-spection of the marginal distribution forsalaries (2) showed that virtually no re-spondents reported salaries between$40,000 and $70,000 but approximately 1.5percent reported salaries in excess of$70,000. This is a small proportion, yetthese inaccurate responses deviate so ex-tremely from central tendency that theycan add substantially to the variance in sal-aries.

Accordingly, we eliminated from ouranalyses all respondents reporting base sal-aries of $50,000 or more. Some who re-ceived less than $5000 could have beencoded as having salaries, say, just under$50,000, but since our analysis was con-fined to full-time faculty and few full-timefaculty members made less than $5000 in1972 73, we considered this risk accept-able. Before the respondents indicating sal-aries of $50,000 or more were eliminatedthe standard deviation for salaries was$10,601, an obviously anomalous datum toanybody familiar with faculty salary distri-butions and one that should have madeBayer and Astin aware that something wasamiss. After those cases were eliminated,the standard deviation for males was $5769and for females $4484.

In preparing this comment I decided toattempt a replication of Bayer and Astin'serror. I ran a regression of females' sala-ries on several independent variables with-out using the $50,000 cutting point and ob-tained results comparable to Bayer andAstin's: the multiple correlation coefficient(R) turned out to be .38, slightly higherthan Bayer and Astin's .29 primarily be-cause of the introduction of a larger num-ber of independent variables and perhapsbecause several dummy variables were cal-ibrated differently. I know this result to beerroneous, because in our analyses of ayear ago using the $50,000 cutting point wefound that we could account for 66 percentof the variance in female salaries (R =

SCIENCE, VOL. 190

.82). This result is comparable to the oneobtained from similar data in 1969, whenR was .76 for females. It is therefore im-portant to recognize the untenability ofBayer and Astin's speculation (1, p. 800)that their surprisingly small R for females

indicates substantially greater difficulty in pre-dicting 1972 73 salaries of women than of men.The 1968-69 study showed higher multiple cor-relations and substantially greater similarity inthe degree of predictability of men's and wom-en's salaries (men, R =.81; women, R =.76).These shifts in results between 1968-69 and1972-73 suggest that the traditional criteriaused in the awarding of salaries may be in theprocess of being abandoned or reformulated, orat least are not being uniformly applied to wom-en and men throughout the various sectors ofacademe.

Even on a strictly intuitive basis it seemsinconceivable that the multiple correlationcoefficient for females could have droppedfrom .76 to .29 in 4 years (3); such anerosion of a reward system obviously couldoccur only in a situation of virtual anarchy.

With the erroneous data eliminated, themultiple correlation coefficient for femalesappears to have increased slightly between1969 and 1973 (.76 to .82), and that formales appears to have decreased slightly(.81 to .77). Such a change suggests as a so-ciological hypothesis that, in a conflict-la-den environment where some factions raisequestions about the legitimacy of rewardprocesses, such processes tend to becomemore formula-dominated, particularly asapplied to those who have raised questionsof legitimacy. Administrators are increas-ingly pressed to justify decisions on fe-males' salaries with reference precisely tothose variables that Bayer, Astin, and Ihave introduced into our equations. I ven-ture to predict that as we obtain moretime-series data we shall find that "luck"becomes a progressively smaller factor infemales' salaries, while such a trend maynot exist at all, or to the same degree, formales. In any case, since the Bayer-Astinspeculation about the "abandonment" or"reformulation" of salary determinationprocesses for females implies that lucknow plays a much larger role than former-ly, it may create a dangerously erroneousimpression in the minds of academicianswho believe that the most effective mannerof restoring legitimacy consists, in part, ofleaving fewer matters to chance.

MICHAEL A. FAIADepartment ofSociolog_,College of William and Mary,Williamsburg, Virginia 23185

References and NotesI. See, for example, Chron. Higher Edu. 7, 9 (5

August 1974); Behav. TodaY 5, 210 (12 August1974).

2. Findings cited in this comment are based on a 15percent random sample from the American Councilon Education file containing data on more than50,000 faculty members.

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3. Bayer and Astin's salary data for 1968-69 werebased on a questionnaire item in which respondentswere asked to indicate their institutional salariesby checking one of nine income categories rangingfrom "below $7,000" to "$30,000 and over."This item did not invite response error in the man-ner of the 1972 73 item.

4. The 1972 73 faculty data used as a basis for thiscomment were collected by the American Councilon Education's former Office of Research undera grant from the Research Applied to NationalNeeds (RANN) Division of the National ScienceFoundation. Access to the data was achievedthrough the Council's Division of EducationalStatistics, Washington, D.C. I thank the ComputerCenter of the College of William and Mary for theuse of data processing facilities.

Faia faults the article by Helen Astinand me for errors in procedure, results, andinterpretation which are apparently his,not ours. He is, however, correct in that wedid encounter some difficulty in our surveywith a small number of the responses to theitem requesting salary data from academicpersonnel. A few of the 53,000 respondentselected not to disclose their salaries in thesurvey, and 15 percent overlooked report-ing whether their designated salaries wereon an academic year (9 to 10 months) or acalendar year (11 to 12 months) basis. Atrace, 409 individuals out of 53,000 re-spondents, or 0.77 percent, reported sala-ries in excess of $70,000, some of whichwere clearly spurious although others inthis salary range can be presumed to becorrect inasmuch as our sample includedmany chief administrative officers as wellas eminent scholars. Faia's reported pro-portion of 1.5 percent above this salary lev-el would appear to mistakenly includethose who omitted the salary item.The brevity required for our Science ar-

ticle precluded detailed description of thefull procedure we employed to draw oursubsample for the analyses. We wereaware of the possible misreporting of sala-ries in the high ranges, however, and allsalaries in excess of $40,000 were analyzedfor their presumed consistency with the re-spondents' rank, degree level, length ofservice, publication productivity, or ad-ministrative responsibilities. In the sub-sample of 4998 cases used in our analysis,12 men and 6 women who had incomesabove this level were retained in the sampleunder the presumption that their incomeswere reasonable, given their status androles. All respondents who did not reporttheir salary, or did not report the basis oftheir salary, were excluded from our sub-sample. The resulting subsample standarddeviation on income was $6410, not Faia'serroneous $10,601 which apparently was

derived by including coded omitted re-

sponses to the salary item (scored as " 100"and thus possibly analyzed by him as

$100,000 salaries).We also did not interpret our findings

with respect to the poor predictive resultsof salaries for women by adopting Christo-

pherJencks's "luck" explanation (1). Noris a "situation of virtual anarchy" a neces-sary "only" feasible interpretation of suchresults, as Faia claims. An alternative ex-planation which we suggested is that a lowmultiple correlation coefficient could beobtained if some institutions had institutedbroad corrective actions to adjust theirwomen faculty members' salaries whileothers had done little or nothing by 1972-73 in response to recent antibias legisla-tion.

It nevertheless remains perplexing as towhy Faia's results with respect to one ofthe prediction equations would deviate sosubstantially from ours, particularly in-asmuch as he has employed our data.Faia's attempt to replicate our earlier1968-69 study with our 1972-73 data, col-lected by us for the same purpose, has untilthis time resulted in only an early press re-lease, subsequently picked up by the semi-popular press, which he cites in his letter.Only if he reports his study in full in a ref-ereed scholarly journal, where peer ap-praisal by the scientific community mighttake precedence over media publicity,might the discrepant results which heclaims be more adequately understood.

ALAN E. BAYERDepartment ofSociology,Institutefor Social Research,Centerfor the Study of Education,Florida State University,Tallahassee 32306

References

1. C. Jencks et al., Inequality a Reassessment of theEffect oJ Family and Schooling in America (BasicBooks, New York, 1972).

Mixed Blessing

The Science cover of 12 Septemberraises a curious coincidence. The captionfor the distressing photograph of the deadchestnut reminds us that the tree's deathwas caused by the fungus Endothia para-sitica, a species whose extracellular pro-ducts enjoy the incongruous distinction ofbeing the subject of a food additive regu-lation, under the Food, Drug, and Cosmet-ic Act. The federal regulation for fermen-tation-derived, milk-clotting enzymes[number 121.1199 (CFR 21)] provides forthe use in cheese manufacture of the en-

zyme produced by pure culture fermenta-tion of E. parasitica. Pathogenic for some

trees, apparently, but beneficial to man.DONALD H. WILLIAMS

Dairy and Food IndustriesSupply Association, Inc.,5530 Wisconsin A venue, NW,Washington, D.C. 20015

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