Spinco Model H Electrophoresis-Diffusion Instnmment

Electrophoresis-Diffusion facilities for high-precision research uses are combined in the

Spinco Model H Electrophoresis-Diffusion instrument, illustrated. Having multiple optical

systems arranged for rapid and efficient use, an optimum of automatic controls, and a single-

unit construction, the instrument features ease and convenience of operation.

With the development of this unit, reliable, reproducible laboratory procedures

are routine in the isolation, separation, and identification of materials having electrically

active particles. New applications are constantly developing in the fields of complex-colloid

analysis,production control of purified proteins, and the discovery ofnew factors.

For data on this new instrument, or on Spinco ultracentrifuges-the world-wide

standard in their field-write:

Spinco wBECKMAN INSTRUMENTS, INC. BECKMANBELMONT 5. CALIFORNIA

I

Any fungus that can be cultured on Sabouraud'smedium may be cultured and identified moreeffectively on this new Mycological PaperMedium.

GROWTH on this new medium appears earlierand pigment, if any, appears sooner and is moreclearly defined on the reverse white side. Identi-fication on this medium can generally be madein about 2/3rds the time required for Sabou-raud's medium.

New culture medium will last practically indefi-'

Uninoculated

nitely and needs no refrigeration. May be simplyreactivated, when dry, by the addition of a medi-cine dropper full of sterile water. It contains noantibiotics.

All colonies remain localized and generally donot overgrow one another. This is of considerableimportance when contaminants or saprophytesare present. Bacterial growth is also inhibited andlocalized on this new medium.

Cultures may be preserved more effectively forrecord and display purposes.

T. purpureum C. albicans

DIRECTIONS: Store in cool place. Refrigeration is unnecessary. Inoculate inthe usual manner with exudate or scrappings of the lesion involved, keeping caploose. Incubate at room temperature and examine after several days for evidenceof growth. When growth is obtained, examine reverse white surface for pigment.

ORDER TODA MY!MYCOPAPER MEDIUM-BOX OF 12 Vials (Ready to Use) .. .......0

*34 West 4th Street

NewYork 12, N Y.

SCIENCE is published weekly by the AAAS, 1515 Massachusetts Ave., NW, Washington 5, D.C. Entered at the Lancasis; Pa., Post Office as second clau~~~matter under the act of 3 March 1879. Annual subscriptions: $7.50; foreign postage, $1; Canadian postage, 5O0.

Ecdcom

16 MARCH 1956 435

recommended by the leading medical schools,hospitals and laboratories

D STUDENT MICROSCOPES

DEPENDABLE-Scientifically engineered and manufactured by the world'sforemost microscope manufacturer, Leitz STUDENT Microscopes with preci-sion optics are built for a lifetime.

VERSATILE-Leitz STUDENT Microscopes of standard dimensions are suitablenot only for the medical student but are recommended as well for lateruse in office practice, hospital and clinical laboratories.

Labolux A new concept in microscope design combining coarse

and fine focusing adjustments in a single control, resulting in utmostsimplicity and convenience. Low-position controls for fatigue-freeoperation. Stage, not tube, moves for focusing. May be used facingthe observer for greater accessibility to all controls.Labolux S 47/92-15 Built-in mechanical stage; Abbe condenser; quadruple nosepiecewith achromats 3.5x, lOx, 45x, 1OOx oil-the two high-powered objectives havespring-loaded mounts; paired 6x and lOx eyepieces; including professional carryingcase: $579.50

Monocular-Binocular Model "B" A convertible microscope of classicdesign with ball-bearing fine adjustment, trouble-free operation,triple or quadruple nosepiece with magnification range from 21to 1000 times. Unique dove-tail slide permits quick interchangeof tubes.

BS 25a/92-lOa Inclined Binoculor; built-on mechanicol stage; Abbe condenser;triple nosepiece with achromats lOx, 45x, 100x oil; paired 6x and lOx eyepieces;including professional carrying case: $527.00

Monocular Microscope Model "G" A first-class precision instru-ment with full-size laboratory stand, large diameter monoculartube. Full range of plain and mechanical stages available, as well

as triple or quadruple nosepiece.GO 47/92-10 Monocular; mechonical stage; Abbe condenser; triple nosepiece withachromats lOx, 45x, 100x oil; 6x and lOx eyepieces; including professional carryingcase: $331.00

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E. LEITZ, INC., Dept. SC-3, 468 Fourth Ave.,, New York 16, N. Y.

Please send me the STUDENT Microscope brochure.

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E. L E ITZ. INC., 468 FOU RTH AVENUE., NEWV YORK 106, N. Y.Di stri butors of the worl d -f am o u s prod u cts of

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M ICRO-PROJECTOR

Brighter, clearer images...faster, easier operationHere's the answer to crowded classes and limitedinstruction time. Projects more vivid views ofmicroscopic specimens easier to see and understand-than any other budget-priced micro-projector. That'sbecause of its efficient combination of high qualityobjectives, double lens condensing system, pre-focused100-w. lamp, focusable stage plate and objective holder,and vibration-free stand.

You'll appreciate its simplicity, too. In just seconds you canadapt it to projection of (1) screen images of preparedmicroscope slides, (2) screen images of livingmicro-organisms in liquid, and (3) table-top imagesfor tracing. There are many other important advantagesto help make science teaching easier-and more effective.Wouldn't you like to know more about them?

WRITE FOR FREE CLASSROOM DEMONSTRATIONand for informative Catalog E-248, Bausch & Lomb OpticalCo., 64203 St. Paul St., Rochester 2, N. Y.

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SCIENCE, VOL. 123438

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PHOTOCONDUCTIVITY CONFERENCEEdited by R. G. BRECKENRIDGE, National Carbon Company, B. R. RUSSELL, The College of Wooster,

and the late E. E. HAHN. With 46 contributors. Covers the subject of photoconductivity, stressing basictheory, phenomenological theory, interpretation of photoconduction phenomena, and the most recent dataon the properties of important photoconductivity materials. 1956. Approx. 630 pages. Prob. $13.50.

ELEMENTARY CRYSTALLOGRAPHYAn Introduction to the Fundamental Geometrical Features of Crystals

By M. J. BUERGER, The Massachusetts Institute of Technology. A penetrating study of the symmetryproperties of crystals, which are basic to all other phases of crystallography. Gives you a firm foundation insymmetry theory that can be easily understood with only a background in high school mathematics. Care-fully planned tables and over 600 illustrations illuminate the discussion. 1956. Approx. 562 pages. In press.

THE EXAMINATION OF NEW ORGANIC COMPOUNDSBy WALTER T. SMITH JR., University of Michigan, and RALPH L. SHRINER, State University of Iowa.

Contains a collection of methods used in the quantitative analysis of organic compounds. Semi-micro meth-ods are used, but certain macro-methods are given also. Most of the methods in this manual have beenselected from articles in the literature and rewritten so as to be useful to readers unfamiliar with such analy-ses. 19 5 6. Approx. 144 pages. Prob. $ 3.5 0.

THE SYSTEMATIC IDENTIFICATION OF ORGANIC COMPOUNDS, 4th Ed.By R. L. SHRINER, State University of Iowa, R. C. FUSON, and D. Y. CURTIN, both of the University

of Illinois. Many changes have been made in this edition, most of them emphasizing the research-laboratoryapproach to the identification of organic compounds. New chapters have been added on infra-red and ultra-violet spectroscopy, mixed melting points, and control reactions. 1956. 426 pages. $6.00.

RESONANCE IN ORGANIC CHEMISTRYBy GEORGE W. WHELAND, University of Chicago. Differs from the conventional treatment of the

subject in its explicit concern with the application of quantum mechanical methods to problems ofmolecular structure. At the same time, the author's approach is uniformly chemical. Includes an appendix ofinteratomic distances and bond angles which lists all the data obtained by all experimental methods for theentire range of organic'chemistry. 1955. 846 pages. $15.00.

ANDROGENS: Biochemistry, Physiology, and Clinical SignificanceBy RALPH I. DORFMAN, Boston University, and REGINALD A. SHIPLEY, Western Reserve University

School of Medicine. The first and only work devoted specifically to the broad subject of androgens. Com-piles, summarizes, and evaluates the available material in the literature on male hormones and related ster-oids. It emphasizes the clinical aspects of androgens and the occurrence of overlap between various syn-dromes. Also includes a unique coverage of the concentrations of 17-ketosteroids in health and disease. 1956.590 pages. $13.50.

Send for examination copies.

JOHN WILEY & SONS, Inc. 440 Fourth Avenue, New York 16, N.Y.16 MARCH 1956 469

*for

SPE(IAM APPLICATIONSModel "K"

For sectioning of unde-calcified bone, plastics,and other extremely hardmaterials.

Model "Tetrander"For large specimens inparaffin or celloidin em-beddings.

Model "L"

Immersion microtome forbrain and lung sections.

Microitome KnivesFinest surgical steel, ofall profiles, for every ap-plication.

Write or phone today for further details

WILLIAM J. HACKER & CO., INC.82 BEAVER STREET, NEW YORK 5, N. Y.

Telephone BOwling Green 9-8750

U.S. Representative forJUNG, farnous for pre-cision microtomes andknives since 1872.

1BIOCHEMISTRY AND THECENTRAL NERVOUS SYSTEM.

The subject of chemical change andstructure in the central nervous sys-tem is in the forefront of biochemicaldiscovery. 43 illustrations. 33 tables.

$9.50CLINICAL DISORDERS OF HY-

DRATION AND ACID-BASE EQUI-LIBRIUM. A lucid examination of thepathogenesis and treatment of fluid andelectrolyte balance. "Fills an importantgap in medical literature. Well written,concise and represents the carefullyconsidered judgments of one who hashad extensive experience in this area."-DR. HOMER SMITH. 249 pages, 11 fig-ures. $6.00

- QUANTITATIVE METHODS INHISTOLOGY AND MICROSCOPIC

HISTOCHEMISTRY. "An extremely use-ful book which should certainly be thefirst reading task of any histologist orcytologist who feels perhaps he couldincrease the value of his work by usingthe quantitative approach."-Journalof Histochemistry and Cytochemistry.

$5.50- HISTOCHEMISTRY: THEO-RETICAL AND APPLIED. "The

first important work in its field since1949; it is logically organized, beauti-fully written and thoroughly indexed."-Journau of the AMA. 122 ilustra-tions, 13 in color. $12.00

For immediate deliveryuse this ad as your order form

and mail to your medicalbook dealer or directly

to the publisher_ _ ___---o-

w

16 MARCH 1956

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