SCIENCE-ADVERTISEMENTS

..-1

A Selected List of

WILEY BOOKS IN Is* TEXTBOOK OF GENERALZOOLOGY

By W. C. CURTIS, Professor of Zoology, andMARY J. GUTIRIE, Professor of Zoology;both at the University of Missouri

A detailed study of the facts concerningstructure and function of animals. Ap-proach is through a study of vertebrateanatomy. ("Laboratory Directions in Gen-eral Zoology," by the same authors, isparticularly planned as an accompanyingmanual. Third edition, 1939, 195 pages,

Third edition; 1938;682 pages; 6 by 9); $3.75

* ELEMENTS OF BIOLOGYBy PERRY D. STRAUSBAUGH, Head, Depart-ment of Botany and Zoology, West VirginiaUniversity, and BERNAL R. WEIMER, Pro-fessor of Biology, Bethany College, WestVirginia

A one-semester textbook stressing principlessubstantiated by factual material. ("ANew Manual for the Biology Laboratory, byWeimer-Core, was written for use with thistextbook. 1944, 213 pages, $2.00.)

1944; 461 pages; 5) by 81; $3.25

* GENERAL BIOLOGYBly I'ERRY D. STRAUSBAUGH and BERNALWEIMER

A more comprehensive treatment than "Ele-ments of Biology,'" by the same authors, thistextbook gives a fundamental understandingof structure and function, and pictures theorganism as a whole.

1938; 555 pages; 6 by 9); $3.75

* INTRODUCTION TOVERTEBRATE EMBRYOLOGYBY WALDO SHUMWAY, Professor of Zoology,University of Illinois

A modern physiological approach to prob-lems of embryology, as well as the classicalmorphological treatment. Emphasis is dy-namic and upon patterns and mechanics ofthe different stages of development.

Fourth edition; 1942;372 pages; 6 by 9); $4.00

* AN INTRODUCTION TOTHE VERTEBRATES

By LEVERETT A. ADAMS, Professor of Zool-.ogy, University of IllinoisProvides an outline of the characteristics onwhich the modern system of classification isbased, and gives a general 'view of each ofthe five classes, as well as a comparativeanalysis of anatomical systems and special-ized structures.

Second edition; 1938;479 pages; 6 by 9); $3.50

* INTRODUCTION TOPARASITOLOGY

By ASA C. CHANDLER, Professor of Biology,The Rice InstituteCompletely revised, this edition contains theresults of the many advances in this field inthe past few years. Human parasitology isemphasized.

Seventh edition; 1944;716 pages; 5) by 81; $5.00

* GUIDE TO THE STUDY OF THEANATOMY OF THE SHARK,THE NECTURUS, THE CAT

By SAMUEL bEDDY, Associate Professor ofZoology, C. P. OLIVER, Associate Professorof Zoology, and J. P. TURNER, Late AssistantProfessor of Zoology; all at the Universityof MinnesotaA manual to serve as a guide in dissectingthe animals described, this book is excellentfor laboratory courses in comparative anat-omy. ("Atlas of Outline Drawings of theDogfish Shark, the Necturus, and the Cat forVertebrate Anatomy," an aid in studyinganatomy of these animals. 1940, 77 sheets,$1.50.)

1939; 100 pages; 6 by 9); $1.50

* ESSENTIALS OF HUMANEMBRYOLOGY

By GIDEON S. DODDS, Professor of Histologyand Embryology, West Virginia UniversityWritten primarily for medical students, thisbook presents embryology from the humanrather than the comparative view.

Third edition; 1945;314 pages; 51 by 8); $4.00

JOHN WILEY & SONS, Inc., 440-4th Ave., New York 16, N. Y.

.1

m

February 15, 1946

SCIENCE-ADVERTISEMENTS

The most important scientific books of the past yearwill be shown at the

SCIENCE LIBRARYOf the 113th A. A. A. S. Meeting

St. Louis, March 27-30

At each meeting of the A. A. A. S. the leading scientific publishers combine to presenttheir foremost publications of the preceding year in the Science Library. In additionmany of the companies have their own individual exhibits with additional books ondisplay.This year, the Science Library will have an unusually large and outstanding collectionof fine books. In many instances, material recently released from military securityregulations will be available for the first time. Extra space has been allotted to theScience Library so that there will be adequate facilities for leisurely inspection andreading of the many books on display.As in past years, the March issue of The Scientific Monthly will carry a listing of allbooks submitted for deposit in the Science Library up to the time the issue goes topress. And at the meeting a reprint of the listings, together with important announce-ments by the publishers and other exhibitors, will be distributed free.Trained librarians will be in attendance at the Science Library at all times and willassist those who wish to order books from. the various publishers.Visit the Science Library at the meeting. It is arranged for your enjoyment andinspection by the cooperating publishers.

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SCIENCE-ADVERTISEMENTS

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By DR. EMMETT JAMES CABLE, head ofthe Department of Science at Iowa State Teach-ers College; DR. WILLIAM H. KADESCH.Professor of Physics, and DR. ROBERT W.GETCHELL, Professor of Chemistry.An up-to-date revision of an outstanding scienceorientation course for school and college use.Included in this latest edition are such "in thenews" topics as radar, atom-smashing and tele-vision-and other vital, modern aspects of sci-ence that must become common knowledge totoday's student.

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Aerobiology consists of the papers of a symposium presented at the meetingof the Association held in Chicago on September 22-24, 1941, in connection withthe celebration of the fiftieth anniversary of the founding of The University ofChicago. The symposium was organized by the Section on Medical Sciences andthe Committee on Aerobiology of the National Research Council, under the direc-tion of Dr. E. C. Stakman, Dr. Stuart Mudd, Dr. E. B. Lambert, and Dr. MalcolmH. Soule.

The volume consists of two distinct parts, extramural aerobiology and intraomural aerobiology. Extramural aerobiology, in which part there are eight pa-pers, is concerned with the distribution of living organisms by the exterior air andwith some of the consequences of their distribution. It includes within the fieldof interests insect population, plant pathogens, and fungus spores.

Intramural aerobiology, in which part there are 29 papers, is equally diverseand important. It begins with the problem of contagion by air-borne infectiousmaterials. It investigates the expulsion of secretions from the mouth and nosein the acts of sneezing and coughing; it follows the infections from the dissemi-nation of pathogenic organisms into the operating room, the hospital ward, thecubicle for infants and the school and the home.

viii + 296 quarto pages (7i x 10O inches),10 plates and 75 illustrations, references

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SCIENCE-ADVERTISEMENTS Vol. 103, No. 266814

SCIENCE-ADVERTISEMENTS

Notice to Subscribers and ContributorsCommunications relative to articles offered for publication

should be addressed to Editor, Massachusetts and NebraskaAvenues, Washington 16, D. C.

Communications relative to advertising should be ad-dressed to Theo. J. Christensen, Massachusetts and NebraskaAvenues, Washington 16, D. C.

Communications relative to membership in the Associationand to all matters of business of the Association should beaddressed to the Permanent Secretary, A.A.A.S., SmithsonianInstitution Building, Washington 25, D. C.

Communications relative to subscriptions from nonmembersshould be directed to The Science Press, North Queen St. andMcGovern Ave., Lancaster, Pa.

15

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SCIENCE-ADVERTISEMENTS Vol. 103, No. 2668..

,'.%

Mercury vapor from spilled droplets ofmercury hidden in crevices throughout thelaboratory may over a period of time reachthe toxic concentration point and be in-jurious to the health of the laboratoryworkers. The toxic limit for continualbreathing as established by the AmericanStandards Association (Report Z 37.8-1943) is 1.3 parts of mercury vapor in 100million parts of air by volume. By deter-mining the concentration of mercury vapor

in the air precautions can be taken to keepthe mercury-vapor concentration below theharmful limit and safeguard the health ofworkers exposed to the vapor.

No. 20150 Mercury-Vapor Detector util-izes a chemical method for detecting as

little as seven parts of mercury in 100 mil-lion parts of air in one hour. In six hoursthe apparatus will indicate that the toxiclimit has been reached. The apparatusconsists of a truncated cone which acts as an

air chimney mounted on a suitable stand.A reasonably constant temperature and anupward flow of air through the cone are pro-vided by a 25-watt red Mazda lamp in thebase of the cone. Fastened to the top ofthis chimney is a curved paper holder, pastwhich the upward air draft must flow. Theholder accommodates strips of selenium-sulfide-sensitized paper j inch wide by 2inches long. A cross-draft eliminator, in theform of a cylinder mounted around theholder, is provided to prevent air, other thanthat from the chimney from striking thepaper.

indicating the concentration of mercuryvapor in parts per 100 million parts ofair are provided with each instrument.When the sensitive paper has been ex-

posed for the required length of time, itscolor is matched with the nearest of thesix shades on the horizontal scale whichindicates the various concentrations ofmercury vapor.

An exposure of only one hour is re-commended (A.S.A.), though this shortexposure will not detect concentrationless than seven parts of mercury per 100million parts of air. Detection of thetoxic limit (1.3 parts per 100 million)requires about six hours.

A calibrated color chart with a horizontalscale of six shades of gray for matching withthe exposed paper, and a vertical scale for

No. 20150 Mercury-Vapor Detector is designed for operation on115 volts. Price ........ $50.00

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REPLIES to box number advertisements should be sent to the Advertising Department for forwarding.

POSITIONS OPEN

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It is expected that several Benjamin Peirce Instructorshipsfor teaching mathematics at Harvard University will beawarded for the academic year 194847. The salary is $3,000for a two-term year. Renewals up to three years are pos-sible. Teaching programs are slightly more than nine hoursper week and usually Include at least one half course ofgraduate level. A candidate should have several testimonialletters appraising research promise and teaching ability sentdirectly to the chairman of the Department of Mathematicsat Harvard.

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Index to Advertisers

Name Page

American Association for the Advancement.........................

American Optical Company ........................ Cover 4

Bausch & Lomb Optical Company ....................... 209

University of California Press .................. Cover 2

Fred S. Carver 12

Farms, ..........................

Central Scientific Company ................ ......... 16

Classified Advertising ......... ................ 17

Clay-AdamsCompany, Inc . ................................

ComstockPublishing Co., Inc.....................................DifcoLaboratories ..................................................................

The Gaertner Scientific Corp ................... Cover

Gradwohl School of Laboratory Technique ...

International Equipment Company .....................

TheKimac Company ............................................................

KlettManufacturing Company .................................

LaMotte Chemical Products Company ...............

Merek &Company ..................................................................

S. B. Penick & Company..................;

PhotovoltCorporation........................................................

Prentice-Hall, Ine...................................................................

Radio Corporation of America .................. Cover

211

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W. B. Saunders Company.

Standard Scientific Supply Company. 18

F.J.Stokes Machine Company .................................

TheTechniconCompany ...................................................

W. M. Welch Manufacturing Company ............

Westinghouse Electric Corporation ......................

John Wiley & Sons, Inc. .............

3

8

7

9

Wyeth,Incorporated ..................................5

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

i

18 Vol. 103, No. 2668 '

i N #' \ - . Slana, ret

:.EW RC.A VACUUM: UNIT

speeds many laboratory-and factory processes

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