-~ ~~~ ~ ~ ~ ~~~~~~~~~~~~~~-l l

I/ I

, ~~~LEITZ PANPHOTI I

' _ ~~UNIVERSAL

I II I

CAMERA-MICROSCOPE

t I

I~~. I

Here is the universal camera-microscope subject to be photographed. The camerawith which you switch instantly from accommoda15Ies 3/4x 4 1 plates or cutobservation to photography. You simply film (for black and white or color work) .

shift a prism in the body tube. Per- It is adaptable to 4' x 5n plates or films.manently aligned research microscope, ThLizPn ot ivraCme-reflex camera and light source are Microscopewas designedforutmostver-combined in one convenient unit. The satility. It can be quickly and easilylight source of the Panphot provides a adpetoheUrpk,hsemc-

filaent ampfor bseratin an an scopy, dark-field work, observation un-arc liht fophotoicrogaphy.der polarized light, and many other uses.

Ground glass in the mirror reflex cam- E ET,N. itiuo fwrdfmu

I I~~~~~~~~~~~~EKT9 N.,dsrbto fwrdfmu

era gives you a clear, large image of the products of Ernst Leitz, Wetzlar, Germany.

E.Leltz RMnc.Dept. SC_ B ^ j _ ~~~~~~~468Fourth A-venue, New York 16, N. Y.I

wG% w ~~~~~~~~~~Pleasesend meyour brochure on the Leitz Panphot Universal- W ~~~~~~~~~~Camera-Microscope.I

microscopes Name_I

b1noculars _ _ILelca camer Compay I

lenses Street_City State I__~ ~~~~-- - - - - - - - - - - -- - - - - - - ----

___________________

3 JUNE 1955 9A

t'77d1AUTOMATICpackard FRACTION COLLECTOR

Provides Both Time and Drop Counting OperationFor the Most Precise Fraction CuttingRequirements of Chromatographic Work* Drops from column fall directly into test tube. * Any number of drops from 1 to 400 cai

No intermediate glass arms or funnels- collected in each tube for drop counting.possibility of mixing, contamination or evap- time intervalfrome 4 to 100 minuiteoration is eliminated. This is especially im- operation.portant where accurate sep)arations are * Turntable be indexed by of "1lrequired or where certain fractions are labeled ual Index" switch for convenience in setwith radioactive tracers. up experiments.

* All principle parts-turntable, phototube housing, etc.-are made of stainless steel.

Price complete for time and drop counting .... .......... $795.00Price for time operation only ......................... $535.00

Send for completeinformation today I

Packard Instrument

CompanyDept. A., P.O. Box 428

LaGrange, Ill.

M akers of Complete Electrophoresus Apparatus

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

3 JUNTE 1]955

I

B A C TOCONCENTRATION DISKS

Bacto-Concentration Disks are for deter-mination of penicillin level in milk, seruiim,urine and other body fluids.

The concentr-ation disks contain measuredamounts of penicillin.

The following standardized materials are

recommended for this procedure:

Bacto-Penicillin DisksBacto-Penase DisksBacto-Subtilis Spore SuspensionBacto-18'hey Agar

DIFCO LABORATORIESDetroit 1, Michigan

Complete details of this procedureavailable upon request.

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

n beAny

,s intiiiie

Man-tting

m

IIA

-PERSONNEL PLACEMENTI

1lllllllllllttIt[I0IItPOSITIONS WANTED |||||||||||||||||||Endocrinologist-Biochemist, M.S., experience in biological assays,pituitary-adrenal studies, and hormone-ageing relationships. Desiresindustrial research or academic position. Prefer Western states.Box 158, SCIENCE. X

Parasitologist, Ph.D. Twenty years exceptional background infield and laboratory research and teaching veterinary and medicalparasitology. Numerous publications. Desires research or teaching.Box 156, SCTENCE. X

Pharmacologist: Desires industrial position. Industrial and aca-demic experience: pharmacodynamics, chemotherapy, toxicology.B3ox 159, SCIENCE. X

(a) Pharmacologist; Ph.D.: extensive experience in circulatoryphysiology, autonomic pharmacology and general pharmacology.(b) Biologist, Ph.D., wishes research in radiobiology, endocrinol-ogy with teaching; eight vears' experience research and teaching.Medical Bureau (Burneice Larson, Director), Palmolive Building,Clhicago. X

Physiologist, 27, B.A. medical school physiology department;assistantships; bioassayist pharmaceutical house; trained in organprofusion leading medical center; desires teaching and/or researchmidwest. Box 161, SCIENCE. X

Research Administrator: Clinically-oriented Ph.D. (Chemistry,Plharmacology). Directing clinical research program, ethicalpharmaceutical house. Professional service experience. Extensiveclinical and laboratory conitacts throughout U. S. Desires similarposition, new location. Box 157, SCIENCE. X

.....

Available: one pre-doctoral fellowship, one post-doctoral fellow-ship in biochemistry for study of fundamental problems in enzymechemistry, physical biochemistry, and isolation of natural productsin Department of Biochemistry in leading eastern medical school.Box 162, SCIENCE. X

Biochemist, Ph.D., basic research hypersensitivity, and chemistryantigens and antibodies. Write background. Allergy Research Lab.,Northwestern tTniversity Medical School, Chicago 11. 6/3

(a) Biochemist; M.S.; duties of supervising technician; large uni-versity affiliated hospital; to $5500; East. (b) Associate Biochem-ist; Ph.D.; experienced protein properties and measurements; alsofamiliar protein isolatioti or structure; to $6600; pharmaceuticalhouse. (c) Bacteriologist; M.S. and hospital experience, serology,mycology, parasitology; supervise department, 400 bed teachinghospital, to $5000; East. (d) Physiologist; male; Ph.D. preferred;teaching and development of research program; 12 hours teachingweekly, research in area of own choice; faculty rank instructorto associate professor; Midwestern university, enrollment 5000.Woodward Medical Personnel Bureau, 185 N. Wabash, Chicago. X

Biologist, to work with tissue transplantation and animal genetics;opportunity for personal research; write Director, R.P.M.I., 666Elm Street, Buffalo 3, New York. 6/10, 17

HIIIIIIIDIIIIIIIIIIIIIIIPOSITIONS OPEN |||ill||l|||lllllllllCoders and Abstractors-Ph.D. or M.S. in Physiological Sciencesto cover assignments in world literature on drugs and cardiova,scularsystem. Full or part-time work at home near good medical library.Foreign language knowledge preferred. Box 160, SCIlENCE. 6/10

Literature Chemist-M.S. in biochemistry with minor in organicchemistry to assist senior scientist in literature searching, abstract-ing and evaluation of scientific data. Reading knowledge of scien-tific French and German. Age 24 to 35. Comprehensive benefitprogram. Send complete information of educationi and experience.Box 149, SCIENCE. 6/3, 10

FNOTICE TO SCIENCE TEACHERSIWrite us for your copy of Catalog, 500-H, PHYSICALA ND CHEMICAL APPARATUS - FOR SCIENCECOURSES IN SCHOOLS AND COLLEGES. The mostcomplete, up-to-date, classified apparatus catalog for(science) teachers in the world.

SCIENCE HOUSE, IncorporatedBox 7913, Pittsburgh 16, Penna.

Pathologist: To do research pathology and some routine examina-tion of animal tissue in ethical pharmaceutical firm. LocationMetropolitan New York. Box 163, SCIENCE. 6/10, 17

(a) Pharmacologist, Ph.D. or M.D., well grounded in pharmacody-namics to head operating division of pharmacology, pharmaceuticalcompany, and, also, research assistants in virology and bacteriol-ogy; new research laboratory; East. (b) Chief clinical psychol-ogist; Ph.D.; large hospital outside Continental United States.(c) Associate Biochemist, Ph.D. in chemistry or biochemistry, withemphasis on chemical or physio-chemical aspects of proteins and,also, microbiologist, M.Sc., interested in virology; research de-partment, large company, East. S6-1 Medical Bureau (BurneiceLarson, Director), Palmolive Building, Chicago. X

Wanted: Laboratory instructor for general biology. Mornings freefor advanced study. Salary $2500.00 a year. Box 151, SCIENCE.

6/3

FIhe MARKET PLACE1BOOKS * SERVICES * SUPPLIES * EQUIPMENT

|||||||}IIH||||||BOOKS AND MAGAZINES |||||||||||||||WANTED TO PURCHASE . Sets and runs, foreign

`~S and domestic. EntireCtIEUTIFIs PERIODICALS, libraries and smallerSCILENTIFIC and BOOKS J collections wantedWALTER ). JOHNSON * 125 East 23rd St., New York 10, N. Y.

SCIENCE, VOL. 121

YOUR ad here reaches over 32,000 foremost scientistsin the leading educational institutions, industriallaboratories, and research foundations in the U. S.and 76 foreign countries - at a very low cost

CLASSIFIED: 18¢ per word, minimum charge $3.60. Use ofBox Number counts as 10 additional words.

DISPLAY: Rates listed below-no charge for Box Number.Monthly invoices will be sent on a charge account basis-provided that satisfactory credit is established.

Single insertion $19.50 per inch7 times in 1 year 17.50 per Inch

13 times in 1 year 16.00 per inch26 times in 1 year 14.00 per inch52 times in 1 year 12.50 per inch

For PROOFS on display ads, copy must reach SCIENCE 4weeks before date of issue (Friday of every week).

CLASSIFIED: 25¢ per word, minimum charge $6.00. Use ofBox Number counts as 10 additional words. Correctpayment to SCIENCE must accompany ad.

DISPLAY: Rates listed below-no charge for Box Number.Monthly invoices will be sent on a charge account basis-provided that satisfactory credit is established.

Single insertion $19.50 per inch7 times in 1 year 17.50 per inch

13 times in 1 year 16.00 per inch26 times in 1 year 14.00 per Inch52 times in 1 year 12.50 per inch

For PROOFS on display ads, copy must reach SCIENCE 4weeks before date of issue (Friday of every week).

12A

POSITIONS OPEN

FIhe MARKIET PLACEBOOKS * SERVICES * SUPPLIES * EQUIPMENT

lIlIIIIIIIf IIIIIllffIIIf 1111 BOOKSANDMAGAZINES

YOU CAN PUBLISH YOUR BOOKi Almost 2000 authors-most of them new-have had

their books published, promoted and distributedthrough our unique plan. No matter what type ofbook you've written-fiction, poetry, biography,religious - we can help you Send for our freeillustrated brochure, "We Can Publish Your Book".

EXPOSITION PRESS I Dept. SWI386 FOURTH AVENUE, NEW YORK 16, NEW YORK

IN CALIFORNIA: 9172 SUNSET BLVD., HOLLYWOOD 46

Your sets and files of scientific journalsare needed by our library and institutional customers. Please sendus lists and description of periodical files you are willing to sellat high market prices. Write Dept. A3S, J. S. CANNER, INC.

Boston 19, Massachusetts

|||||||||||||||1!|PROFESSIONAL SERVICES |||||||||||||||

BOOK MANUSCRIPTS INVITEDWrite for Free Booklet SC telling how we can publishyour book. All subjects considered. New authors welcome.

VANTAGE PRESS, Inc. * 120 W. 31 St., New York 1In Calif.: 6253 Hollywood Blvd., Hollywood 28

FOOD RESEARCH RESEARCHLABORATORIEIS,, INC.~ RSAC

Found 1922dkplLSHwk.PID..DP_d 0 CONSULTATIONemn d L Ow, PlD. Dkede

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.......................... .........

* 2 SSWISSMICE I.TACONIC I

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* HYPOPHYSECTOMIZED RATSShipped to all points via Air Express

For further information writeHORMONE ASSAY LABORATORIES, Inc.1 8159 South Spaulding Ave.

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SEA GLESHealthy - AKC Registered - Immunized

$25 to $50 each; F.O.B. IthacaJ. FATULA - Dog Form - RR1 Ithaca, N. Y.

RESEARCH BIOCHEMICALS____ OVER 1500NUTRITIONAL BIOCHEMICALS

Corp.Cleveland 28, Ohio

Write for your copy-free catalogue

3 JUNE 1955

SOUTH SHOREANALYTICALAND:RESEARCH LABORATORY, Inc.148 ISLIP AVE. ISLIP, N. Y.

IIIfI|I|||||I|||II|IIIJIIISUPPLIESANDEQUIPMENT i|||||||||||||||||||||||||j

M~~~~~IC"A" Strain"C" Strain

Medical Center Laboratory519 E. Club Blvd., Durham, N. C.

A - ' T lb AA r C *AL BIIN() 1.tA 1 D "From the hand ofthe veterinarianHYPOPHYSECTOMIZED RATS to research"*Descendants of the Sprague-Dawley

and Wistar Strains

HENRY L. FOSTER, D.V.M.President and Director

THE CHARLES RIVER BREEDING LABS.Wilmington, Mass.

m_

SUPPLIES AND EQUIPMENT11 t.

13A

-The MARKET PLACEIBOOKS * SERVICES * SUPPLIES * EQUIPMENT

n~~~L~~~ 391SUPPLIES AND EQUIPMENT|||||' | | | SUPPLIES AND EQUIPMEINT||||||||||||||||||||

Albino Swiss-W MiceLA KAT RY Albino Rats from Wist. StrainMb11kAIS| C Albino Guinea PigsANItA -AL Albino NZ Rabbits and Hamsters

since ALBINO FARMS1929 P. O. Box 331. vz ~~~~~~~~~~~~REDBANK, NEW JERSEY

All AMINO ACIDS- natural, synthetic, unnatural,Rare Sugars, Biochemical Products, Reagents, NewPharmaceuticals in stock. Write or phone PLaza7-8171 for complete price list.

1BIOS LABORATORIES, INC. New York 23 eN. Y.

Long-Evans (PAF)Wistar (PAF)

Bred for Research Work by Research WorkersPACIFIC ANIMAL FARMS

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FRACTIONATORS * TRANSFERATORSCARDIOVASCULAR RECORDERSELECTROENCEPHALOGRAPHSWARBURG APPARATUS

WATER BATHS I

{l \/wS Igive to

AMERICAN CANCER SOCIETY fe

SCIENCE, VOL. 121

FERMENTOR

An all-purpose laboratoryfermentor which is useful in

obtaining information for

correlation with large scale

fermentations. It is designed-; .; .. .. for the study of all types of

microbial processes. Aerobic

or anaerobic fermentations

by bacteria, fungi, yeasts, or

algae -producing antibiotics,

vitamins, organic acids, en-

zymes, polysaccharides, sol-

vents, or cell proteins can beconveniently observed in this

5 liter pilot plant fermentor.

Detailed information available upon request

NEW BRUNSWICK SCIENTtFIC CO.P. 0. Box 606 * NIEW 9UNSWICK, M. J.

14A

Design

N EW SizesSCHAAR-BLUE M incorporating Easy Operationplus VERTICALLY DIRECTED AIR FLOW

IMPROVED I Now- all purpose, low cost heating units that assure positivetemperature uniformity and quicker operation due to better aircirculation. Powerful turbo blower convects air down rear wall

REC I RC U LATING plenum chamber, over Modella Heater Bank and VERTICALLYTHROL-GHOUT ENTIRE WORKING CHAMBER. Adjustable

UTILITY baffle plate permits reduced air velocity for processing light-weight materials. Extremely versatile, these auitomatically con-

OV E N 5 | trolled ovens offer your laboratory efficient, dependable, longlasting service.

STANDARD MODEL FTemperature Range to 2600 C.

Designed to speed up lalboratory work, this ultra modern model has allthe requirements for laboratory or produiction procedures and providescontrolled, (lean, dry heat. Thermiiostat response sensitivity is ± 1/ C.3" blanket of Fiberglas wool insuilation. Large working chamber is 19" x15" x 18" lughi. Outsi(de dimensions: 27" x 23" x 38" high. Available ineither all stainless steel or attractive, durable gray hammerloid enamelexterior. Suipplied complete with 2 adjustable shelves and terminal box.SN-4850 For 115V, 60 cy., 1/Ph., AC current, 1600 watts. Gray hammer-loid exterior, stainless steel interior with 2 nickel-plated expanded metalshelves - $295.00SN-4855 Same as SN-4850, but for 230V., AC $295.00SN-4860 Same as SN-4850, but all stainless steel inside and outside iwith 2 stainless steel shelves $375.00SN-4865 Same as SN-4860, but for 230 V., AC $375.00

NEW... BUDGET MODELTemperature Range to 2320 C

A smaller scale model incorporating the same quality of performance inwvorking chamber 12" x 10" x 12" high. Outside dimensions: 1512." x161/2" x 29" high. All stainless steel construction inside and out: 2"Fiberglas insulatior. Stupplied with 2 adjustable shelves and terminal box.SN-4840 For 115V, 60 cy.. 1/Ph., AC current, 700 watts. All stainlesssteel interior and exterior with 2 stainless steel shelves ....$225.00

HI-HEAT MODELTemperature Range to 3430 X

The wide temperature range permits this unit to conduct an untusual---

_ _ _ number of laboratory tests oT production Trms. Completely -automatic inoperation, these newly designed ovens provide the ultimate in perform-ance and insure quiick, stable working temperatures with many dollarssaved in operating costs. All six sides are insulated with a 3-inch blanketof Therm-O-Block which forms a perfect thermal equilibrium at hightemperatuires and keeps outer suirfaces cool even after prolonged use.Working chamber has dimensions of 19" x 15" x 18" high. Overall dimen-sions: 27" x 23" x 38" high. Available in either all stainless steel, orattractive, durable gray hammerloid enamel exterior. Suipplied completewith two adjustable shelves, terminal box and indicating-controllingpyrometer. Response senisitivity is + 120 C.

SN-4866 For 230 V., 60 cy., I/Ph., AC current, 360l0 watts. Gray ham-merloid exterior, stainless steel interior with 2 nickel-plated, expandedsteel shelves $545.00

SN-4867 Same as SN-4866, but of all stainless steel construction insider j1andoutside with 2 stainless steel shelves $625.00

6-Hour Automatic Timer For All Models .............. $17.50 additional

To order with timer - add suffix "T" to Cat. No.

For further information,contact your local repre- CA A Asentative or write direct to: AND COMPANY

* Complete Laboratory Equipment 0 Chicago .7, lllinios754 W.. Lexingtc.,n St.

An assortment of 700 itemsin our stock for immediate shipment ...

The brands listed below have been selected for purity, dependability and responsibilityof the maker. Our prices are identical with those charged by the manufacturer.

BIOLOGICAL STAINS, DRYColeman & Bell Dry StainsHarleco Dry Stains and "Parstains"National Dry Stains

BIOLOGICAL STAINS IN SOLUTIONColeman & Bell Stains in SolutionHarleco Stains in SolutionHynson, Westcott & Dunning Giemsa Solution

MOUNTING MEDIA FOR MICROSCOPYA.H.T. Co. Canada BalsamColeman & Bell Balsam, etc.Flatters & Garnett "Euparal"Harleco Resins, etc.

EMBEDDING MEDIA FOR HISTOLOGYA.H.T. Co. ParaffinFisher "Tissuemat"

Copy of Reagent catalogue sent upon request.

SYMBOL OF QUALITY

I LABORATORY APPARATUS

ARTHUR H. THOMAS COMPANY

WEST WASHINGTON SQUARE PHILADELPHIA 5, PA.Teletype Services: Western Union WUX and Bell System PH-72