p _. a

the mew Aggz#w t>" store aud view*,,.~color

o atrnsparenelYou know how efficiently Technicon Lab-aid

cabinets bring order to the filing of microslides,paraffin blocks and associated materials in thepathologic laboratory.

Now, in this new addition to the Lab-aid FilingSystem, you can enjoy the same benefits in thefiling and viewing of color transparencies andlantern slides. The new Lab-aid transparency filehas 40 smooth-sliding flat trays, each holding 16standard 2" mounts, or 5 31/41 x 41/4' lanternslides in full view. They're easy to insert . . .you just drop them flat in the grooved frames.Easy to remove, too, by popping them out fromunderneath.

The special cabinet with its pull-out illuminatordrawer lets you view a whole tray of transpar-encies at a glance, without removing any of them.Sitting or. standing, you can inspect hundreds ofslides under ideal viewing conditions without stir-ring from your place. And the disappearing shelfis a mighty handy place to lay slides down tem-porarily while you're working with them.

Both tray and illuminator cabinets are of thesame dimensions and finish as all the other units

Assembly of Lab-aid in the Technicon Laboratory Filing System, andTransparency Tray Cabi. can be stacked interchangeably with them. If youcabinet drr pulledoumtor would like more information obout these or othercab thet-drb base,or ll units of the system, we'll be glad to send details.stack them with yourpresent Lab-aid Files.

The disappearing shelf Is con-'.,.venient as a temporary restingplace for slides while working Inspect all your slides without re-with -them. moWng any of -thenm, or -even stir? 4

ring from your place. .*

Other units In -the Lab-a.id -line1" MICROSLIDE DRAWER FILES2" SLIDE OR TRANSPARENCY DRAWER FILE'4' SLIDE 'OR 'INDEX "DRAWER FIlESMICROSLIDE FLAT-FILING TRAY CABINET]PARAFFIN BLOCK FILE

TE TECICON COPAN!Y215 lt 149tb St., Now York 51, N. T.

I

- iI Ia -*

- -- -

(I) TELESOPE EXTNSION AMAZING!USED Double Utility!

TELESCOPE - Combination

15X TELESCOPEand 35X Erecting

MICROSCOPEUSED i Extra utility by removingAIvS35x I J telescope portion and using as

MICROP 35 power microscope to in-SCOPE spect, dissect, etc. E±cellent

clarity whether used as tele-scope or microscope. Telescopeobjective lens is achromatic,

coated. Telesoope can be re-moved and carried in pocket-focuses from 10 ft. to

infinity. Microscope has 3 element, color corrected objective-image iserect-itjst as your eye sees it-not upside down as in an ordinarymicroscope. Ramsden eyepiece with coarse or fine focusing. Gives you 3"of working distance when used as microscope. This low price is possibleonly because we utilize some very high grade war surplus parts In

manutfacturing this fine instrument. Entire unit folds down to 2" x 7"x 10". Telescope instantly adjustable in height from 3" to 14".Stoek No. 70,017-W .............. $29.50 Postpaid

Your Chance to Own a Very Fine Instrument

IMPORTED MICROSCOPE100, 200, 300 Power ONLYGood optical qualities. Fine focus-ing. Certainly not the equal of a$200 Instrument but definition Is Pstpd.surprisingly clear and good ***1OUAin fact amazingly so at this price. 1 OCULARServiceable construction. The LENSESCTIVEgreatest microscope bargain on the RACK &market I PINION

TRY IT FOR 10 DAYS If FOCUSINGyou're not completely satisfied DISC-LIGHTyour money will be refunded in ADJUSTABLEfulL MIRROR

SQUARE STAGEInstrument comes packed in (2%" x _xsturdy, hard wood case. 2-5/8") with

SLIDE CLAMPSStock No. 70,008-W -14.95 Postpaid

LOOK AT THESE BARGAINS!BUILD YOUR OWN SLIDE PROJECTOR

Thousands of ouir customers have built their own Projectors-gotten excellentresults and saved a great deal of money. To build a Projector buy our StockNo. 4068-W . . . includes a mounted F/1.9 Projection lens; a focusing mount;2 condensing lenses; heat absorbing glass and full assembly instructions.Stock No. 4068-W .................................... 600 Pstpd.

SIMPLE LENS KITS! - Kits Include plainly written, illus-trated booklet showing how you can build lots of opticalitems. Use these lenses in experimental optics, buildingTELESCOPES, low power Microscopes, etc.Stock # 2-W-10 lenses ....... ............... $ 1.00 PostpaidStock # 5-W--45 louses ......... .......... $ 5.00 PostpaidStock #1-W 880 leses ................. $10.00 Postpaid

IMPORTED POCKET MICROSCOPEADJUSTABLE! 20, 40, 60 POWER!A compact, handy precision instrument of

many uses Select power you want, then focus sharply by turning special micro-focs ring. Good quality optics. Full satisfaction guar-anStod.Stock #30005-W ............ Only S3.95 Postpaid

IF YOUr'RE INTERESTED IN OPTICAI

"rto for FREE CATALOG Iw"&A

POCKET COMPARATORCheck, Measure, Inspect SmallParts and Dimensions with 6POWER MAGNIFICATION

MEASURES A5

* Angles * Radii * Circles '^"t!* Linear

in both decimal inches and millimeters.

I .oJwIjIi.EiL.IL5IruI.nU

aQ -*---....e0A

| < '' '''' '' ' O

0,61-W .......................... .. $22.50 Postpaid

Order by Stock No. Send check or M. 0.

IMPORTEDrEREO MICROSCOPE

at 50%0Saving! e160Wide, S Dimensional Field $160

Excellent Depth for Working Val.Under Magnification! ONLY

v, for the first time-a fine, im-;ed Binocular Microscope at astantial saving. Used for inspec-vs, examinations, counting, check- Fr netc. Fixed 3 power objective with Pstpd. Ij1lirs of matched eyepieces to givepowers of 15X, SOX, 45X. Rack and pinton .1ising. Interpupillary adjustment. Instrumentemovalble from base for mounting on eq ip-Lt or bench. Working distance-2M". Adjust-!for extra height. Fine hardwood case included. Recommendedlab, shop, factory or home use, We guarantee complete satis-ion or your money back.k No. 70,011-W ...................... $85.00 Pstpd.

NEW! 30 POWER TELESCOPEZ + Complete with Tripod Unusual Bargain Price

A beatutifully made, sturdy, imported Instrument with dozens ofuses. Stops 22 caliber bullet holes at 200 yds. You can seethe craters on the moon-observe, close up, birds, animals,etc., see ships far out at sea. Excellent for amateur astron-omers. All metal body-focuses from approx. 40 ft. to In-finity. Achromatic objective-40 mm. dia.-outside surface low/refleetion ted. Smooth slide focusing eyepieee. Eye-lens out-side surface coated. Lens erecting system. Images right side up.Sturdy tripod 8%" high. Can be used also for camera. Max.length 2614". Barrel dia. approx. 1%h". Weight 1% lbs.Steek No. 70,018-W ............... Only $21.95 Postpaid

DiFFRACTION SPECTROSCOPEUses grating replica instead of prisms. En-ables you to see what your photographic flltersdo . . . to see color character-istics of yourphoto light sources. You can attach to your

camera for taking spectograms. A wonderfully useful and practical instrument.Imported from England, A real bargain.Stock No. 50,020-W $.............................. 14.70 Pstpd.

SAVE MONEY ON CUSTOM-MADE AND STOCKRETICLES AND IRIS DIAPHRAGMS

Tell us your requirementsl Send blueprint for quotatIen on your custom-mado neds. For stock Items ask fo Reetlcle Bulletin W or DiaphragmBulletin W.

EYE-PIECE MICROMIETER-Importedl 19 mm. diameter. 10 mm. scale dividedinto 100 parts. Val. $5.00.Stock #30,035-W ................................. $3.50 Pstpd.STAGE MICROMETER-Imported! Rectangular glass slide with photographicscale-1 mm. long divided into units of 0.01 mm. Val. to $10..00.Stock #30,036-W ...............................:S $4.00 Pstpd.REVOLVING NOSEPIECE-Importedl Triple and quadruple. For Standard sizemicroscopes and objectives.

Stock #30,037-W ... Triple. $11.00 Pstpd.Stock #30,038-W .. . Quadruplo ... $13.50 Pstpd.

L BARGAINS OR[ER BY STOCK f0f Send Cheek w M. 0.IyM ldem Wew Swups* Satisfaction Guaranteed-4 for Sbl* owe"Motdofbo_@o To

us ~ ~ ~ ~ ~ ~ ___ _II

September11,I19531---

v

WVW _- .. _.MW

September 11, 1953 1

I

THIS BOTTLE TURNNS

SEVEN YEARS INTO

SEVEN MONTHS

4 Test blocks of pole wood are fed to destructive fungi in

bottles like this at Bell Laboratories. WVood rests onsoil which controls moisture conditions and promotesfungus growth. Test speeds search for better preservatives.

This year the Bell System is putting 800,000 newtelephone poles into service. How effectively arethey preserved against fungus attack and decay?

Once the only way to check a preservative wasto plant treated wood specimens outdoors, thenwait and see -for seven years at least. Now, witha new test devised in Bell Laboratories most ofthe answer can be obtained in seven months.

Cubes of wood are treated with preservatives,then enclosed in bottles with fungus of the mostdestructive kind, under temperature and humidityconditions that accelerate fungus activity. Success-or failure-of fungus attack on cubes soon re-veals the best ways to preserve poles.

The test has helped show how poles can beeconomically preserved for many years. It is an-other example of how Bell Telephone Laboratoriesworks to keep down your telephone costs.

BELL TELEPHONELABORATO R I ES

Improving telephone service for America provides careers forcreative men in scientific and techniccl fields.

aRIe. U. S P%,JPat. Off.

ENZYMESAcetyl Cholinesterose (20,000 U vial)

Amylopsin 3 U.S.P.Alpha AmylaseBeta Amylase

Catalase CrystallineChymotrypsin Crystalline

CocarboxylaseCozymase (coenzyme I) 65% PureCozymase (coenzyme 1) 90% PureCytochrome C (amorphous Powder)

Cytochrome C (liquid)Diastase (malt)

Desoxyribonuclease 1 x Cryst.EmulsinErepsinFicin

GlucuronidaseHemicellulaseHyaluronidase

InvertaseInvertase (Analytical grade with Melibiose)

Invertase (Analytical grade without Melibiose)Lipase

MycozymeMylase PPancreatin

Papain PowderPectinase

PenicillinasePepsin 1: 10,000

Pepsin, 2 x CrystallizedPhosphataseProtease

Rennet N. F.Ribonuclease, Crystalline

Soybean Trypsin Inhibitor, 5 X CrystallizedTriphosphopyridine Nucleotide

(approx. 65% pure)Triphosphopyridine Nucleotide

(approx. 80% pure)Trypsin 1 x Cryst.Trypsin 2 X Cryst

Trypsin 2 x Cryst (salt free)Trypsin 4 U.S.P.

Trypsinogen 1 x Cryst.Urease PowderUncase Powder

A READY REFERENCE _____That will Save Time for You 1G i!

SPECIALPRFODUCTS

Use this catalog as a "one stop" source I"tsi"[cNof Amino Acids, Vitamins, Carbohydrates,Adenylates, Nucleates, Purines, Pyrimi-.dines, Tetrazolium Salts, Enzymes, Micro-biological and Bacteriological Media, WRITE FORComplete Animal Test Diets and YOUR COPYIngredients for investigational use. TODAY

GENERAL BIOCHEMICALS, INC.SI LABORATORY PARK * CHAGRIN FALLS, OHIO

. . recognized through-out the sciences as themost versatile and effi-cient source of transmittedand incident light for routinemicroscopy. A cool burning,intense, dependable lamp, the'E & G Model I features lowvoltage, compactness, focusingdevice, built-in iris, daylight filterand multiple filter holdcr Buy this highquality illuminotor at leading scientificdealers or from monufocturer direct.

ERB & GRAY854 S. Figueroa St. * Los Angeles 17, Calif.

I GLASS ABSORPTION

CELLS obde KLET

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

SCIENCE, Vol. 1184

Every Researcherin biology, drugs

llI_ 1 medicine, endocrinology| | |~eIecarch I

ble tc or allied sciencesonSdrUSpdyt should have a copy of

< ~MARTIN'SBiological Antagonismby GUSTAVE J. MARTIN, PH.D., Research DirectorThe National Drug Company, Philadelphia

In this most comprehensive volume of 1900 references, Dr. Martin presents atheory of biologic relativity as the basis of antagonism, its central concept beingthat specificities in any biologic system are RELA TIVE not absolute.

BIOLOGICAL ANTAGONISM gives the information necessary for replacementdrugs or anitagonistic drugs for counteracting adverse effects. It covers antagon-isms as observed in the field of amino acids, purines, pyrimidines, vitamins, hor-mones and minerals. It descrbes the relationship between pharmacology, physi-ology and chemistry in such studies. It ii THE research volume every researclherin biological work must have.

516 pages, 44 tables, 64 figures $8.50

r mmm mm mm mM m mm m m m m m m m - - -m m m m m m -m m m m m m m

I THE BLAKISTON COMPANY, INC. II GARDEN CITY, NEW YORK

Please send me ............. copies of Martin's BIOLOGICAL II ANTAGONISM $8.50 II You SAVE Postage by Sending Check or Money OrderI O Check or M.O. Enclosed C] Charge My Account I* D~~~~~- Send C.O.D.I

* Name .............

Address.I

* City.... Zone .. State... .

Sci. 9-11-53LI _ _ - _ - _ _ _ _ _ _ _ _ _ _ - m_ _ _ -_ _ _ _ m m m m

September 11, 1953

ACTH * Growth * GonadotropesEstrogens * AndrogensCorticoids * Progesterone

Others

HYPOPHYSECTOMIZEDRATS

WENDOCRINE TOXICITY^ ~TESTS

- Write for details~.0- . *lm~

*

When ACCURACYis important...CASTLE AUTOCLAVES are ideally suited toprecision laboratory work because uni-form temperature is rigidly maintainedthroughout the chamber. This temperatureis selective at any point from 2120F. to260°F., hence adaptable for all routine andresearch work.SINGLE WALL TYPE is generally suitablefor laboratory procedures. It is equippedwith condenser hood which preventsmoisture dripping on contents.DOUBLE WALL TYPE gives you the dryingeffect of a separate pressure jacket. Thistype can be used for general surgicalpurposes.Interior equipment to meet your require-ments. Write: Wilmot Castle Co., 1212University Ave., Rochester 7, N. Y.

Single wall No. 1826-L

fi }j/~ BacteriologicalApparatus

SCIENCE, Vol. 118

C PHOTOVOLT Densitometerfor

Partition Chromatographyand Paper Electrophoresis

A photoelectric precision instrument for therapid and convenient evaluation of strips andsheets of filter paper in partition chromatog-raphy and paper electrophoresisWrite for Bulletin #800 to

PHOTOVOLT CORP.95 Madison Ave. New York 16, N. Y.Also: ColorimetersipH Meters IMultiplier Photometers

Fluorimeters I Nephelometers I Interference Filters

RSTANDARPROCEDURE.to make

STANDARDYour Sourceof Supply

EIMAC

Diffusion PumpThe Eimac HV-1 Diffusion Pump is a fast,

i _ triple-jet air-cooled vacuum pump of theoi-diffusion type. When used- with a suit-

! _ able mechanical forepump and Elmac type Aoil it is capable of reaching Ultimate vac-

uum of 4 x 10-7 mm of mercury. The glassconstruction permits rapid inspection ofconditions within the pump.

APPLICATIONS OF THE EIMAC PUMPEVACUATING Electronic vacuum tubes, etc.,

METAL TO CERAMIC BRAZ-ING, METALIZING BY EVAP_

ORATION, DISTILLATION OF

VITAMINS, VACUUM SMELT-

ING AND CASTING, ANTI-REFLECTIVE COATING, VAC-UUM SINTERING OF METALS,OBTAIN OPERATING PRES-

,SURE of cyclatrons and Y-12, FREEZE-DRY-ING OF BIOLOGICALS.

FEATURES OF THE "EIMAC" PUMP

Pyrex Glass Barrel-Readily enables inspection of oil rings and internaloperating conditions.Simple Cleanlng-This factor Is one of the most Important to pump users.

The "EIMAC" can be disassembled In a matter of minutes without specialtools. Normal cleaning procedure is 100% effective as there are no inac-cessible areas. (With metal-barreled pumps inspection is difficult andeffectiveness of cleaning can be determined only after pump has been re-

turned to service.)No refrigerant-The "EIMAC" is entirely air cooled with the cooling ac-

complished from the draft of a small fan.No Charcoal Trap-The unique cold-baffle prevents entrance of oil vapor

in the high-vacuum manifold.Pipe-Flange Mounting-Both high-vac and fore-pump manifold connectionsmatch standard pipe flanges.110 Volts AC-DC-No complicated electrical circuit is required as theheater operates on standard 110 volt power.

No. 84570 Complete assembly Includes flanges and nipples with gaskets andeomplete Instructions ........ .............. Price $125.00No. 84571 Special type A pump oil ................... Quart $5.00

VACUUM INDICATING GAUGE

This equipment which is designed to operate with the RCA type 1946

thermocouple gauge tube or equivalent, measures pressures in the range .001

to 1 mm Hg. The meter is calibrated to read air pressure directly. The unit

is operated on 110 volt, 60 cycle ac, and consumes approximately 10 watts.

It is mounted in a sloping front cabinet 6Y2" x 10" x 6½"2^.

Operation is particularly simple. Calibration is checked by use of the

same meter that reads the pressure. A ballast type circuit is employed in

order to minimize error due to line voltage variation.

The thermocouple tube may be sealed directly to pyrex systems. An adapter(listed below) Is available for use in connecting the tube to metal vacuum

systems.

In addition to use as a pressure indicator, the gauge is useful for locat-

ing leaks in vacuum systems by noting sudden changes, in reading when a

material such as acetone is sprayed or painted on the suspected part of the

system.

No. 84572, less thermocouple tube .... .................. $69.50

Thermocouple tube, complete with plug to match above gauge circuit $12.50

Thermocouple tube, eomplete with plug and adapted for metal

systems . ..............$......................... S15.00

For Safe, More Efficient Heating IN ALL LABORATORY APPLICATIONS!THE NEW STANDARD HEATER WITH BUILT-IN REGULATOR

the only heater on the market with CONTROLLED TEMPERATURE-NOT CONTROLLED CURRENT:

SELF-SUPPORTING WITH BUILT-IN ROD CLAMPS

The Standard Heater incorporates all the features of safety, durability

and efficiency to satisfy the most discriminating research man. Features

the BUILT-INoclamp, two of which are included with each unit.

Cap. ml Watts Volts500 400 1251000 600 1252000 800 1253000 800 1255000 1000 12512000 1400 12522000 1400 125

Wt.

5 1/4#97#16#

Price$35.0039.5044.3051.5068.6095.00135.00

* CANNOT GET'TOO HOT* DELIVERS FULL RATED WATTAGE* SAFE-PROTECTS FLASKS PROTECTSOPERATOR

ILABORATORY APPARATUS-REAGENTS AND CHEMICALS

September 11, 1953

Cat. #64356A64356B64356C64356D64356E64356F643S6G

I

I

%F

7

WINTHROP

METHYLAMINOACETOCATECHOL3-METHYLTHIOPHENENOREPINEPHRINE

NORLEUCINEORNITHINEPEPSIN

PHENYLALANINEPROBIT PAPERPROTARGOL-S

For the rest of the WinthropAlphabet send for 1953 Price List

Special Chemicals Division

9q-SSNIDNC.1450 Broadway, New York 18, N. Y.

TIME PROVENLaMOTTE SOIL

TESTING APPARATUSThe result of 30 years of extensive cooperative researchwith agronomists and expert soil technologists.The methods used are based on fundamentally soundchemical reactiois adapted to the study of soils, and haveproved invaluable aids in diagnosing deficiencies in plantfood constituents.Methods for the following tests are available in singleunits or in combination sets:Ammonia Nitrogen IronNitrate Nitrogen pH (acidity and alkalinity)Nitrite Nitrogen ManganeseAvailable Potash MagnesiumAvailable Phosphorus AluminumChlorides Replaceable CalciumSulfatesTests for Organic Matter in Soils, and Nutrient Solutions (hydro-culture) furnished only as separate units.

The New LaMotte Soil Sampling TubeThis New Boil Sampling Tube has been designed by ex-perts. It is sturdily built of non-corrodible metals, lightiU weiglht (3% lbs.) and calibrated in 6" intervals foraccuratb soil sampling to any depth to 3 ft. Plastie Vialwith screw caps, for containing soil samples may also behad.

Information on LaMotte Soil Testing Equipmentwil be sent upon request.

LaMOTTE CHEMICAL PRODUCTS COMPANYDept. "H" Towson, Baltimore 4, Md

The RecoCHROMATOGRAPHYDRYING OVENA mechanical convection ovendesigned for heating paperchromatograms.

The RecoELECTRIC

DESALTERFor the removal of inorganicsalts from organic and aminoacid solutions to be chromat-oqraphed.

Fw--~1RACKSIStainless steel or glass for one <I ldimensional chromatography.

INDICATOR SPRAYS _ JFor application of indicators tochromatograms.

) | CLIPS _ JjAll stainless steel spring clips for L jholding chromatograms to glass rods J

SOLVENT TROUGHSFor use in chromatocabsor one-dimensional racks.

ALSO AVAILABLE:

Densitometers . . .for quantitative deter-minations on paper

Ultraviolet LampsPyrex Disc ChambersMicro PipetsChromatocabs

8SCIENCE, Vol. 118

A General Catalogueof the RECO Line ofPaper PartitionChromatographicEquipment Is

Available on Request.

8

LOOK INTO THE

NEW LEITZ

STEREO-BINOCULAR

MICROSCOPE

It's new... modern ... up-to-the-minutel It's stream-lined . .. sturdy ... packed with new featuresIOne ... inclined binocular body tube and adjust-able interpupillary distance for more comfortableviewing.Two... new, improved prism system in stereo tubefor better image quality.Three. . . new rapid-changing device for threeobjectives.Four... objectives protected from damage by newtype mountings.Five. . . binocular body can be rotated through360 degrees for use with offset arm stand.

Six .., redesigned bearing and special steel slid-.ing surfaces insure long trouble-free performance.Seven ... large, 60mm diameter mirror, adjust-able for any desired viewing effect.Eight .., stand of new design with removablestage plate for examining specimens of all sizes.Nine ... special reflected-light illuminators.Ten ... focusing adjustment moving surfaces arelarge to insure accurate focus. And many more!Your Leitz dealer will be glad to show you thismodern new Leitz Stereo-Binocular Microscope.Call him soon.

E. LEITZ, INC., 468 Fourth Avenue, New York 16, N. Y.Distributor of world-famous products of Ernst Leitz, Wetzlar, GermanyCameras * Lenses * Microscopes * Binoculars

September 11, 1953 9

new book announcementsF ~~~~McGRAW-HI LL BOOK COMPANY

THE ACTIN IDE ELEMENTSBy GLENN T. SEABORG, University of California, Berkeley, and JOSEPH J. KATZ, Argonne Na-tional Laboratory, Chicago. National Nuclear Energy Series. Division IV, Volume 14A. Ready inOctober.

Offering material available in no other work, this outstanding comprehensive survey covers detaileddiscussions of the chemistry of all the elements from actinium to the newly-discovered trans-pluton-ium elements. Exhaustive and critical treatment is given to the important nuclear properties of themany isotopes of these elements with special attention to comparative chemistry, chrystallography,oxidation-reduction behavior, and nuclear systematics.

ELECTRICITY AND MAGNETISMBy EDSON R. PECK, Northwestern University. 470 pages, $7.50

This intermediate text provides an unusually careful, clear, and critical discussion of the underlyingprinciples of electromagnetism, including both field and circuit theory, and goes as far as simple ap-plications of the Maxwell equations to electromagnetic waves and radiations. A background in generalphysics and elementary calculus is assumed. Although primarily theoretical, the book maintains con-tact with the laboratory by means of numerous practical problems.

CRYSTAL DISLOCATIONSBy W. T. READ, JR., Bell Telephone Laboratories, Inc. International Series in Pure and Ap-plied Physics. 219 pages, $5.00

A specialized text and reference in a very important phase of solid state physics, this volume is writ-ten for physical metallurgists and physicists interested in the phenomena associated with imperfec-tions in the crystal structure. It explains what dislocations are, what they do, and how they produceeffects which one can study experimentally. Emphasis is upon a systematic introductory account ofwhat is definitely known about dislocations.

WILDLIFE MANAGEMENT: Fur Bearers, Waterfowl, and Fish. Volume 11By REUBEN E. TRIPPENSEE. American Forestry Series. 552 pages, $7.50

This second and final volume of the authoritative study concisely brings together pertinent facts onmanagement of water and wet lands; life histories, ecology, and management of fur bearing ani-mals, waterfowl, and freshwater game fish, and presents necessary procedures for their abundantproduction and orderly harvest. Descriptions of their habitats are also included. Outstanding illus-trations show points of both beauty and interest.

Send for copies on approval

10SCIENCE, Vol. 118

McGRAW-HILL BOOK COMPANY.330 West 42nd Street * New York 36, N. Y.

10