"LAB-AID" EXPEDITERS-they speed-up laboratory chores

F^dmKu1OURn paraffin knifemakes work with paraffin-embedded tissues quickand easy. Great for cutting large blocks into smallones; for mounting blocks on a microtome objectdisc; for squaring up blocks; for separating ribbonsin a water bath . . . Hollow stainless steel handledoesn't heat up - easy to keep knife at the righttemperature. When not in use lay knife in saddle

110 Volts AC DC rest-Blade UP indicates knife hot; Blade DOWN,*,_25 Watts knife cold.

1 1CIlIIiCOfl microslide dryerdelivers slides ready for staining in 7 minutes! Justdrop slides, in an Autotechnicon Slide Carrier, into thehatch, flip the switch and close the cover. A steadycurrent of warm, filtered air blowing over the slidescarries away all moisture, leaving them bone-dry anddust-free. The filter is replaceable. There's no distor-tion, either the warm clean air is well below themelting point of paraffin.

C m iaon.t>¢watrbathinsures smooth, even spreading of your tissue ribbons.The water temperature is just right- never too hot ortoo cold, thermostatically held at any set temperaturefrom 200 to 60°C. There's no melting paraffin to dis-tort tissues - no folds or wrinkles, no bubbles due tofrequent water change. Temperature stays constant,day-in, day-out. And it's easy to see your sectionsagainst the dull finished black interior of the bath.

Size: 103/4" Diam; 33/4" HighSturdy; durable; water and O

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xylolproof finish.110yVoltroofish. AC -THE TECHNICON COMPANYChauncey, New York

Send me literature and prices on

El Technicon Paraffin KnifeEl Technicon Microslide Dryer_ Technicon Constant Temperature Water Bath

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AUTOMATIC FLOW COUNTERAvailable only from Tracerlab for automatic radio0-assays either in the Geiger or proportional region.The instrument accepts 25 samples of a'ny size upto 1 7/8" D by" 5/16" high, with. choice ofappropriate chamker sizes. Each sample may becounted from one to four times in cyclicalorder, or the unit may be set so that the cyclesare repeated indefinitely. The SC-50 may be

~~~~ ~ ~~~~used - either with the Superscaler or Auto-scaler and rosults are printed on a tape by

~~~ ~~~~~ ~~the Printing Interval Timer, a unit de-%Ifr~~~~~~ signed spe'cifically for nuclear.use. Please

request Tracerlog No. 57, for completedetails.

LOS ANGELES * PARIS * CHICAGO * CLEVELAND

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17 JUNE 1955 *1A

that ~is= extremelyx a RCOND T ONED>~AIR CONDITIONEDuseful for cultivat-ing microorganisms TEST CABINETunder conditions of

aeration and with RANGE- up to 1500 F (dry bulb). With refrigeration,more precise temper-.moure temper dew point temperatures as low as minus 300F. Controlature control than is of relative humidity from 5% to 95% is obtained at all

possible in an incubator. It is particularly valuable in temperatures in this range. Air capacity is 200, 400 or

obtaining bacterial growth curves. 600 f. Dimensions are 30"x 28"x 24'.

Detailed information available upon request METHOD -Air is saturated in the air-conditioning unitat the required dew point temperature and re-heated tothe desired dry bulb temperature. No moisture sensitive

NEUtW BRIUNSWICKt SCIENTIFIC instruments are needed. Recorders obtain a completeNEW BRUNSWICK SCIENTIFIC COU record of conditions.-:18 Write for complete information. Address Dept. SW

P. 0. Box 006 . NMWBNUNSWICK,N.J. NIAGARA BLOWER COMPANY

405 Lexington Ave., New York 17, N. Y.

| @@GIvcuronoIactoneA- Useful Pharmaceutical Intermediate

Glucuronolactone and the salts of Glucuronic Acid can reactwith a variety of organic compounds. The Glucuronic mole-cule contains three basically different functional groups

aldehyde (or hemi-acetal), hydroxyl, and carboxyl (or lac-ltone). Requests for information are cordially invited.

ROTARY WATERBATH SHAKER

* Variable speedrange 85 to285 osc. per min.

* Temperature range30°C. to 100°C.

* Available forshaking varioussize flasks.

A shaking aDnDaratus_

2A SCIENCE, VOL. 10-1

INSTRUMENT FOR RESEARCH

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BAIZERS Interference Filtersfor isolating narrow spectral bands

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Flame Photometry and Color Densitometry

Microscopy and Photomicrography

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also In refiectometry light scattering measurements,

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Write for Bulletin 180 to

PHOTOVOLT CORP.

95 Madison Ave. New York 16, N. Y.

PHOTOVOLTLine-Operated ElectronicMULTIPLIER-PHOTOMETER

Mod. 520-M

For the exact measurement of light values as low as1/10,000 microlumen . . . for absorption and flamephotometry, colorimetry through microscopes, scintilla-tion measurements, fluorescence trace analysis, etc.

Write for Bulletin #360 to

PHOTOVOLT CORP.95 Madison Ave. New York 16, N. Y.

SCIENCE is published weekly by the AAAS, 1515 Massaehusetts Ave., NW, Washington 5. D. C. Entered at the Lancaster, Pa., Post Office as secondclass matter under the act of 3 March 1879. Annual subscriptions: $7.50; foreign postage, outside the Pan-American Union, $1; Canadian postage, 50¢.

17 JUNE 1955 3A

MICROBIOLOGY andTISSUE CULTURE

The following Schwarz Preparations are available toassist and extend studies in metabolic and enzymicfunctions:

ADENOSINE PHOSPHATESNUCLEIC ACIDS AND METALLIC NUCLEATESNUCLEOTIDES AND NUCLEOSIDESPURINES AND PYRIMIDINESSUGARS AND SUGAR PHOSPHATESGLUTATHIONE COMPOUNDSSULFHYDRYL REAGENTSTHYMIDIN ECOZYMASEL- AND D-AMINO ACIDS, Optically StandardizedRADIOCHEMICALS, Isotopically Labeled with C14 or S35

These Schwarz Preparationls meet the exacting require.ments of products intended for use in biochemical re-search. Write for informative technical bulletins, com-plete specifications and references to literature. *L *a0

SCHWARZ LABORATORIES, INC.Leading Manufadurers of Yeast Biochemicals and Fine Chemicals

230 Washington Street, Mount Venmon, N. Y.

SCizNCz, VOL. 121

COMPOSITION OF SCIENTIFIC WORDSROLAND WILBUR BROWN

Geologist, U. S. Geological SurveyCONTENTS: Foreword; Abbrevhtions and Sym-

bols; lJistory and Nature of the English Language;Nature of Greek and Latin; Tranoliteration; Dia-critical Alarks; Creek and Latin Wbrds; Formationof Scientific Terms; Adoption of *ords; Composi-tion of Words; Arbitrary Creation of Words; Gender;Spelling and Pronunciation; Cross.Reference Lexi-con; Bibliography; Index.

This new book is designed for all persons interestedin the derivation and coinage of words, but especiallyfor scientists who need new words for new concepts.The first 61 pages describe how words are mate andtlie remaining 821 pages supply the materians andexamples for making them. The comnprphenuive lexi-con is a two-way arrangement of English and' cl#ssicalitems combined in one alphabetic sequence.; Thus,classical roots, listed under appropriate English keywords, can be found readily by the wordmaker.

An indispensable tool for the scientist!A fine gift for an intelligeimt friend!

Bound attractively and sturdily in blue cloth,stamped in gold.- 6" x Y9, 882 pp.

Price $8.00 prepaid. Order directly from theauthor at U. S. National Museum, WVashington25, D. C.

RECTANGULAR IARS forcChromatography

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F.O.B. Berkeley

RESEaRCH SPECIALTIES CO.1148 Walnut e Berkeley 7, Calif.

.10

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KEN CALIBRATED RADIUM STANDARD KIT

This kit contains five permanent standards for the testingand calibration of any counter, scintillatar, ionization cham-ber, Geigerscope or any other radioactivity detector. Theycover the range from 100 to 1,000,000 disintegrations perminute. Complete with accessories and data sheet givingthe certified alpha, beta and gamma activities of each ofthe five standards. $5

KEN RADIOACTIVE ORE SPECIMEN KIT

For comparison or display purposes. Four rich mine sam-ples from different paurts of the country are attractivelypacked in a pocket size clear plastic box. They contain all

X. five of the commercially important radioactive ores. Com-plete with data sheet giving the identifying characteristics

-~and mineralogical properties. .Only $2

SHORT WAVE ULTRA VIOLET BULBAn inexpensive seurce of short wave ultra violet rqdiation. Excitesluorescence in tungsten ores, carbonates and other minerals which donot react to long wave UV. Complete with special socket, simple wiringdiagram anyone can follow, direction and data sheet. $3

KEN ULTRA VIOLET FLASHLIGHTOur research staff has now developed a completely port-able ultra violet l'ight for the use of the uranium prospec-tor. Compact, sturdy and rugged and operates on ordinaryflashlight batteries. The powerful beam will cause fluores-cent uranium minerals to glow at a distance of ten feet.Complete except for batteries so you can use fresh onesfrom your local store. Data sheet lists fluorescent minerals.JUST THE THING FOR THAT NEXT FIELD TRIP. $3

Phone:Hubbard 7-4341

681 MAIN ST. HACKENSACK 7, N. j.

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KEN BEADTEST KITThe sodium Iluoride head test is one of themost sensitive for detecting and confrminguranism minerls. It enables you to distinguishbetween ranium and thorium. The vial ofpure sodium fluoride meets ACS specifications,enough for hundreds of tests. The bead holderIs of PLATiNUM wire, wermanently sealed Intoa heat-insulating handle; foreops are provided.All attractively packed in a convenient easethat you can slip Into your poeket. Completewith direction sheet. Only $2

ATOMIC PROSPECTOR'S HANDBOOKValuable data on radioactive ores, field, lab and mill methods,and map. Everything you need know about this vital new field!Send for Handbook today! Only 1

KEN RESEARCH INC.831 FIFTH AVENUE, RIVER EDGE, N. 1.Gentlemen: I enclose $ ............ in (cash) (check) (moneyorder). Rush the items I have checked below. Each item will besent postpaid and with an unconditional money-back guarantee.QUANTITY ITEM

( ) Professional Model Geigerscope @ $5.( ) Ken Calibrated Radium Standard Kit @ $5.

Ken Radioactive Ore Specimen Kit @ $2.Ken Atomic Prospector's Handbook @ $1.

, ( ) Ken Bead Test Kit (. $2.Short Wave Ultra Violet Bulb `@ $3.Ken Ultra Violet Flashlight @ $3.

Ship them immediately to:

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17 JUNE 1955

KEN KITS for everyone interestedin Uranium and Atomic EfnergyEACH KIT IS UNCONDITIONALLY GUARANTEED OR MONEY SPROMPTLY REFUNDED

THE PROFESSIONAL-MODEL GEIGERSCOPEOptical uranium and radio-activity detector. Now in use In hundreods of laboratories,In industry, atomie energy plants and major universities. More sensitive for use onradloaetive samples or mineral speelmens than any portable electronic instrument,reprdless of price. Sturdy, durable, portable as a pocket watch. Requires no powersorme because It converts the onergy of alpha rays directly Into visible signals; nobackground count. Detect and measure any alpha-active Isotope down to the rangeof a millionth of a microcarle. Detets leakage In x-ray machines, contaminationof air, surfaces, hands, apparatus, not revealed by conventional Instruments. Measoreradioactive fallout from distant ncelear explosions. Invaluable for anyotie inteetedIn radloaetivIty. Supplied eomplete wlth calibrated radium standard, uranim onsample, direction sheet and air-tight holster. $5

DESIGNEDfor research

BUILT

for travel

Completely portable, completely flexible, the Contoura-*Constat*is the only photocopier versatile enough to copy anything, any-where. Formulae, books, periodicals, technical data, drawingscan all be copied without removing them from the reference roomor library-you don't have to waste time on laborious note taking.The Contoura's patented plastic light cushion lets you copyeven the pages of thick, tightly bound books without the usualdistortion at the binding. With the Contoura-Constat you cancopy anything printed, written or drawn; and it's as portable asyour brief case. * T.M. Reg. U.S. Pat. Off.

Write for full details

F. G. LUDWIG, Inc. | 750 Coulter Street* Old Saybrook, Conn.

Depend on Clay-Adams . ..The preferred source of supply for leading hospitals,laboratories and teaching institutions. Qualityproducts through leading scientific deal-ers everywhere. Our 216-page catalogdescribes 1161 products.

,Clay-, dams141 East 25th Street - New York 10

Look for these familiar trade names-your assurance of qualitylAdams Centrifuges . Yankee Rotators . Gold Seal Slides andCover Glasses * Adams Laboratory Counters . Counting Chambers

Yankee Shakers . Medichromes

SCIENCE, VOL. 121

GLASS ABSORPTIONCELLS made KLETT

Makers of Complete Electrophoresus ApparatusSCIENTIFIC APPARATUS

Klett-Summerson Photoelectric Colorimeters-Colorimeters - Nephelometers- Fluorimeters-Bio-Colorimeters - Comparators - Glass Stand-ards-Klett Reagents.

Klett Manufacturing Co.179 East 87 Street, New York, New York

INSPECT BEFORE YOU BUY

U 1ME C () Binocular MicroscopeModel E3N

Highly Praised By Leading ScientistsOne states, "Not one high priced, famous brandI've used can boast a quality that surpasses theE3N."Outstanding Features

Calibrated Mechanical Stage to 0.1 mm-ABBE 3-lensCondenser N.A 1.4-Graduated Decentering Device-Research Type Substage for Polaroid workuad-ruple nosepiece: Achromatic, 5X lOX, 4X,lcoated-Monocular tube for pioto-micrography-Three Eyepieces: Huygenian, 5X, lOX, ?5X- Magni-Lication: 25X to 1500X with monocular tube, m-creased to 30X to 2250X Binocular-lOOX Oilimmersion coated.

MIONEY BACK GUARANTEEWrite for complete Specifications and PricesUMECO OPTICAL Dept. 5S

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Only Bausch & Lomb gives youthe Magna-Viewer projector screen-high-contrast images for easierstudy at selected magnifications.

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* Uniform image brightness, center to edge;easy to see in full room illumination.

A flick of a switch instantly shifts image to microscope or 5 x 7 camera(25 X to 2000 X magnification). You remain comfortably seated,fatigue-free. And ... the Magna-View*er is just one of the many B&Ladvantages that make it easier for you to do your best work.

SEE FOR YOURSELF IN AN ACWrite for obligation-frinformative Catalog E-]cal Co., 75942 St. Pau.00:-''f''t' .. 11 !lilS! £ .....11

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TUAL DEMONSTRATION!ree demonstration and for232. Bausch & Lomb Opti-.1 St., Rochester 2, N. Y.

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8ASC IEN CEI<, VO1I. 1 "218A