eas

thres teanwrtoevrlboraor filin ned in th ;0;jeseo

i--0: -::0 a; -- kt:--:0--0-

0-0:.:0.i; . t0- - D -- 0;-0- 0 - .................. s | .. K | | | S |~~~~~~~~~~~~~~~~...........D : .'0.,',,0'"-,''.'.',,.........'.S.i';V"X'-:.... 's-_

ith ere gesl stni

D'0t0'Vffff ~~~.'''0d.t'.'',-.',-''... ... ... .. ''."''' .0,':'"00..:f0

laborbtor sa atoraefilingi::;;nterchang lE i.t jst.;:.ig<k ........... i"9;"nits.0 0:0:. :> ;;;0t;:; ~~~~~~~~~~~~~. .....*-_ *

2 SLID D RTRANSPARENCYDRAWER SR -RS*

.4" DRAWERS.k-- mw. Fg. L^B.v.: . . . . :L-::-::--000-i-0: - -0Y - 1::l - - - s

;00~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ W: -;V0jva X-t;- - r-'-or3:'S+-'Z'$'tl'S"P"""" '''''sOr

~~~~~~~~~~~~~~~~~ta-SWOI, R S'40P Inf~ ~ ~ crsifnlunm00tZ*dr awer forv bvrlt-in000

ELareFvsbe ci:0ta glance)*-.- FLA-..:T FOR TRANSPARENC..S ciency. For examle.he.niqu.(W0;iOFLA.TidR OWIng) Everythfngabout Technicon Lab-aid file is de-

tt'00 0 00 w ¢ ¢ig

b<,2.t.ii)Q2<< signed to speed the work and improve filing effi--..:::.0.: cy: For example the:-:unique& (paRtented) springFLAIMI-N2 Z

slide-spacers. Holding slidesurgtwhplnyo000000~~~~~~~~~~~~ XX;00 i ; n i 4 v 0 0 0 Z 0 pi^ W, 0;I g0i| 4

Ia; ar-space for quicker drying , they're sti 'll supple* :I UILLUMINKT enoujw :. 0.;iE.S o can easily file or

(used in usel w;;nd!with 000{ 0 ~find a slide. If you want more capacity for close-enyFlat-filing ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~packed,permanent storage, you simply remove the-* PARAFFINSOK FL

PAshallow' d..aw.....wt vais which gives you room for approximately

...do~ c..t.i.r 6500 slides in a single 19" x 19" x 5" unit up to

JS;naleb inets an ri se iab OSbbliesyof wr wr ts th system for

W-:Tech nilcon' Lab-aid rc

laboratory filing, send the coupon

p *a4 fi~~~~~111ng system

THE TECHNICON COMPANY

215 East 149th St., New York 51, N. Y.

Send me particulars of the "LAB-AID" filing system.

Address

City State

Matheson, Coleman & Bell Reagent

Chemicals include practically all of the

items used in research and analytical

work. The Reagent Inorganic Chemi-

cals carry upon the label a statement

showing the maximu4m limits of impuri-

ties allowed. The Reagent Organic

Chemicals are manufactured to pass

the specifications shown in our price

list. In Caldaitionto Reagent Inorganic

and Organic Chemicals we offer many

items of U. S. P., N. F., Practical and

Technical quality.

Complete stocks of MC&B items are carried at our East Rutherford

and Norwood plants and are availabie either through your laboratory

supply dealer or from the East Rutherford or Norwood offices.

Our new catalog listing 3911 Reagent And... asalwfiChemicals, Biological Stains, Chemical THE MATHESON cO'

Indicators and Solutions will be sent to carries the most diversified

uponrwooduplant. and are a either through yourine available ofyousupon request.ofm eaRhf oNr dfCOMPRESSED GASES and

GAS REGULATORS

Jul:17.1933 zizfi*. s w*o : :M*^J , 1o

July 1 .. 19-,3 I

Study Arteriolar Changes Directly weiththe NEW Leiti Capillary Microscope

This improved Leitz capillary microscope brings a new simplicity tothe study of arteriolar changes. Variations in capillary morphology canbe viewed easily and directly in the nailbed, the conjunctiva and theforearm.

The Leitz name on this capillary microscope is your assurance oflifetime precision and dependability. Each instrument is guaranteedagainst any defect in mechanical or optical construction.

For complete details write to Department SC.

E. LEITZ, INC., 468 FOURTH AVENUE, NEW YORK 16. N.Y.

DISTRIBUTOR OF WORLD-FAMOUS PRODUCTS OF ERNST LEITZ. WETZLAR, GERMANY

SCIENTIFIC INSTRUMENTS 0 BINOCULARS * LEICA CAMERAS AND ACCESSORIES

SCIENCE, Vol. 118

MICROSCOPES 0

2

This "LUBRI-TACT"feature makes the

JAGABl a

Better Rheostat LUBRISLII

The "Lubri-tact" CON

consists of a graphitedcarbon lubricator which

slides with the phosphor-bronze current-carrying brush.The resultant smooth actionminimizes wear on theresistance winding ...

insures precise, positiveadjustment and long life.Jagabi Rheostats haveseveral other featuresthat help make themrugged and dependable.They are fully describedin an illustratedbulletin.

We stock JagabiRheostats in 8,10, 16 and20inch lengths and in 76 ratingsfrom 30,000ohms,.1 amPere down to .34 ohm, 25 am-Peres. We also make sPecl tyPes.

El

2 RESEARCHBIOCHEMICALSISFor

INVESTIGATIONAL USE

WRITE FOR

NEW

CATALOGUE

#S 998

Listing over 900Research Biochemicals

TYPICAL NBCo. PRODUCTS

AMINO ACIDSA complete selection of more than 90 amino

acids of maximum purity. Including natural L o

synthetic DL and resolved L and D amino acids.

NUCtEOPROTEINS - PURINESPYRIMIDINES

Adenosine Triphosphate * Adenine - AdenylicAcid * Cozymase * Cytidine * Cytidylic Acid * Cytosinec Desoxyribonucleic Acid * Fructose and Glu-cose Phosphates * Glutathione * Guanine and Salts -Guanylic Acid * Hypoxanthine * Inosine * Nucleate* Ribose Nucleic Acid * Desoxyribonucleic Acid -Ribose * Protamine * Thymine Uracil * Uridine* Uridylic Acid * Xanthine * Xanthosine.

"VITAMIN FREE" CASEIN(Hot Alcohol Extracted)

A valuable source of protein nitrogen of excep-tional purity for incorporation into diets to producevitamin deficiencies.

MISCELLANEOUS BIOCHEMICALSAlpha Keto Glutaric Acid * Cytochrome C

Glutamine * Dopa. Glycogen * Heparin * Lysozyme* Crystalline Vitamins * Crystalline CarbohyrtesFatty Acids * Growth Factor Analogs * Enzymes

* Biological Test Diets * AlkaloidL

SCIENCE, VOl. 118

FREEZE-DRYI NGfor Histologic Preparations

Model FD-1 1

Small, compact * semi-automatic * excellent visibilitysimple, sensitive electronic vacuum gauge * drying periodsregulated by size of tissue (20 permanent blocks or more canbe prepared in 48 hours) * stmple and efficient infiltrationunder vacuum.Freeze-drying is now practical for your laboratory. Wehave pioneered in the simplification and improvement ofhistological freeze-drying equipment. Costly non-essentialsare eliminated with resulting greater simplicity of operation.

Complete with accessories $575. F.O.B. BostonWrite to Dept. S-1

SCIENTIFIC SPECIALTIES CORP.Snow and Union Streets Boston 35, Mass.

II

safety is important in

laboratory glassware, tooThe rabbit is a wily creature. When he selects a home, hemakes sure that it will be safe from his enemies.

Experienced laboratory instructors are mighty careful inselecting laboratory ware, too. They know, for example,that PYREX brand laboratory glassware assures maximum

safety, even to the most inexperienced students. They knowthat they get a plus value, too-real lasting economy.

There are two reasons for this: First, the durability offamous PYREX brand glass No. 7740, itself. Second, thefunctional design of test tubes, condensers, cylinders, fun-nels and other items in the PYREX ware line. All are de-signed to place strength where needed most. Firepolishedrims, reinforced seals and heavy construction reduce break-age.Why settle for less than the safest, when it is also the

most economical laboratory ware you can buy? Call your

laboratory dealer today. He stocks the complete line.

i:i:,iW.-::

.E

TEST TUBES-Wellannealed,with uniform,substantial walls to in-

sure against breakage.Heat resistant, chem-

ically stable.

GRADUATED CYLIN-

DERS-Designed forutility. Sturdy hexag-

onal base providesextra stability, pre-vents rolling if cylinder

is laid on side. Rein-forced rim reduces

breakage.

PYREX BRAND FUNNELS-Allkinds-fluted, plain, long stem,short stem, big diameter, smalldiameter, and stemless, all rug-gedly fabricated from theheavy beaded tops to the fire-polished tips.

the laboratory glassware that gives you eGonomy, accuracy, durability

CORNING GLASS WORKS, Corning, NewYorkzf*rw4.4mzma e#-'e al'-w-e

5Julv- 17, 19543

Another 5' Contributionto Medical Progress

--~~~

Binocular Mi'osC e (Model E 3 N) CONVENIENT for parenteral administration when dilutedsearch technicians, physicians and with Water for Injection U.S.P. TRIPTIDEscientists. Instrument complete for (sodium glutathione) may be used clinicallyvisual and photomicrography. and experimentalyIncludes Monocular tube for photo-micrography . . . IN THE STUDY OF alloxan-induced diabetes, hy-Calibrated mechanical stage e d t , s

3-Lens NA 1.4 Condenser perglycemia due to ATH, shock radiaton ex-Calibrated ABBE DECENTERING, posure, renal dysfunction, detoxication, potas-dCalbrated Condenser Diaphragm sium toxicity, peptide synthesis, and otherSubstage revolves for Polaroid work enzymic functions.

Four nosXepiecOeX cohrmatic. 5X, EACH VIAL PROVIDES 2.00 gm. "of reduced glutathioneThree eyepieces: Huygenian. 5X, in lyophilized, sterile, pyrogen-free form.Magnification: 25X to 150OX with AVAILABLE to allqualified investigators in the fields ofwith binocular.t i biochemistry. Inquiries on TRIPTIDE (sodium

Special introdhciocur. glutathione) are invited.Also Inquire About Our Very Fine Student Microscope

Write for free folderUNION MEICANTILE CO., INC. LABO-RATORIES, INC.

465 California Street San Francisco, California 230 Washington St., Mount Vernon, N. Y.

Drying Problem Solved PHOTOVOLT Densitometerwy Newv mRetn0 forIby .NeMeho CHdROMATOGRAPHIYI

New, Niagara "Controlled Humidity" Method pro-vides air at precise conditions of temperature andhumidity an permits accurate variations of suchconditions at will, in the range of 34°F. to 140°F.;also below 320. if recuired.

This Method uses' Hygrol" liquid absorbent to re- \move moisture from the air 'directly, saving the costof refrigeration for dehumidification. Operation iscompletely and reliably automatic; the absorbent isre-concentrated as fast as it is used.

It is used successfully in drying processes, controlof hygroscopic materials, preventing moisture dam- A photoelectric precision instrument for

ageto materials or instru- the rapid and convenient evaluation ofments, providing con- strips and sheets in filter paper chro-trolled atmosphere for matography and paper electrophoresis

testsadexperments. Write for Bulletin N 800 toUnits provide capaCity CORPranges from 1000 c. f.m. PH T VO Tto 20,000 C. f. M.Wrt f lti 20,( 0 c. £ m..|95 Madison Ave. New York 16, N. Y._agx * ~Write for BulletinNo. 112; address Niagara Also

_ - 02ff Blower Co., Dept. W, || Colorimeters pH MetersBlowerCo., Dept. SW,Fiuorimeters Electronic Photometers405 Lexington Avenue, Reflection Meters Multiplier Photometers

__ New York 17, N.Y. Interference Filters

SCIENCE, Vol. 118

Finest Japanese Optics and WorkmanshipBuilt to our specifications. Priced farbelow comparable values. Be assuredof a lifetime of excellent performance.Equal to the World's finest optical in-struments.Student Microscope (Model UMC300)An unusually fine piece of work-manship. Suitable even for makingblood count and other laboratorywork within the range of its mag-nification.Stand inclinable to 90'.Objectives: Achromatic: lOX 20X.

epieces: HuygenianO 5X __Maniiction: 50X to SQWt. in case: 5 lbs.

Specially Priced| $40.00 |

there Here are eightmust be distinct reasonsa reason why Hanw-SeI

is the preferredcleaner- for labora-tory glassware.

* Completely Soluble* Leaves No Residue* Fully Haemo-Digestive* Lower Surface Tension* Scientifically Formulated* Controlled pH* Multiple Laboratory Uses* Greater Economy

lor literature and sampleswrite

MEINE2ck & COMPANYJIC.225 Varick St. * New York 14, N. Y.

LABORATORYCAGES andEQU-IPMENT

All shapes and sizes of cages areavailable at Bussey's. Stock items are cus-tom tailored to your individual requirements.Our Permaweld construction means more--strength, longer wear, better appearance.

rack,,automatic;- K watering systems or

complete equipment forIS.the housing and care of loboratory animals- Write for catalog or submit yourspecifications. No obigatino.

BUSSEY PRODUCTS CO.P,6000 W. 51st Street* Chicago 38, Illinois

UN-DECALCIFIED~BONE & TEETHand other extremely hard speci-mens sectioned ultra-thin with the

MODEL K MICROTOME

For complete information write

WM. J. HACKER & CO., INC.82 Beaver St. New' York 5, N. Y.

July 17, 1953

Adlk,dm,AlkAm ANkAlikAskAlk 1. Alk AmkImIm lalk Im Idil., lob, Idlik Id& Alk Alk All. Alik 1.

IVm

144444444II444

7

* Cut from machine drawnflat strips of preeision

controlled thickness

* NOW OFFERED AT REDUCEDPRICES BECAUSE OF LOWER

PRODUCTION COSTS

Showin '/2 oz. round wooden boxes and cartoncontaiMing twelve l/2 oz. boxes (6 ounces)

NON-CORROSIVE, RED LABEL

MICRO COVER GLASSESCut, selected and packed in Philadelphia from the same excell Chance micro sheet

sold by us with great satisfaction continuously since 1902, improved fomtime to time, butnow mechanically drawn in strips, which method of production offers the advantagesof flatness and precision controlled thickness as compared with former method of handblowing. Offered from stock in a wide variety of thicknesses, sizes and shapes-see pp.887 and 888 of our catalogue. Outstanding characteristics are:

0 High resistance to attack by moisture0 Freedom from brittleness

* Flatness@ Precision controlled uniformity of thickness

-ARTHUR H. THOMAS COMPANY

WEST WASHINGTON SQUARE PHILADELPHIA S, PA.

Teletype Sevces: Wester. Union WUX and BeN Sysrtm PH-72

SCIENCE, Vol. 118

Per ox. Per oz.Per in 6 oz. 144 oz.

ounce *carto nts7020. SQUARES, No. 1, 18 mm, 22 mm and

25 mm .......................... 1.96 1.76 1.47Ditto, No. 2 ........ ............ 1.64 1.48 1.23

7022. CIRCLES, No. 1, 18 mm, 22 mm and25 mm ............ ............. 3.12 2.81 2.34Ditto, No. 2 ........ ............ 2.68 2.41 2.01

7024. RECTANGLES, Small, No. 1, 22 x 30mm up to and including 22 x 50 mm 1.96 1.76 1.47Ditto, No. 2 ......... ........... 1.64 1.48 1.23

7024. RECTANGLES, Large, No. 1, 24 x 50mm and 24 x 60 mm ..... ....... 1.98 1.78 1.49Ditto, No. 2 ......... ........... 1.66 1.49 1.25

7024. RECTANGLES, Large, No. 1, 35 x50mm up to and including 48 x 60 mm 2.52 2.27 1.89Ditto, No. 2 ......... ........... 1.98 1.78 1.49

One size, shape and thickness only.

8