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Adriance and BrisonPROPAGATION OF HORTICULTURAL PLANTS.

314 pages, $5.50AhlgrenFORAGE CROPS. 418 pages, $6.00BrownCOTTON. Second edition. 590 pages, $6.50Carroll and KriderSWINE PRODUCTION. 498 pages, $6.00CruessCOMMERCIAL FRUIT AND VEGETABLE PRODUCTS.Third edition. 906 pages, $1 1.00DicksonDISEASES OF FIELD CROPS. 401 pages, $6.00Eckles, Combs, and MacyMILK AND MILK PRODUCTS. Fourth edition.

454 pages, $5.75EllikerPRACTICAL DAIRY BACTERIOLOGY.

391 pages, $6.00Fernald and ShepardAPPLIED ENTOMOLOGY. Fifth edition. In pressGardner, Bradford, and HookerFUNDAMENTALS OF FRUIT PRODUCTION. Thirdedition. 739 pages, $9.00GustafsonCONSERVATION OF THE SOIL. 312 pages, $5.00SOILS AND SOIL MANAGEMENT. 424 pages, $6.00Hayes and ImmerMETHODS OF PLANT BREEDING. Second edition.

In pressHealdINTRODUCTION TO PLANT PATHOLOGY. Secondedition. 603 pages, $8.00MANUAL OF PLANT DISEASES. Second edition.

953 pages, $12.50HerringtonMILK AND MILK PROCESSING. 343 pages, $5.00HuttGENETICS OF THE FOWL 590 pages, $7.50JennyFACTORS OF SOIL FORMATION. 281 pages, $5.50JullPOULTRY HUSBANDRY. Third edition.

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495 pages, $6.50

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new!

Willier, Weiss and Hamburger-Analysis of Development

This collaborative work is a modem synthesis of our knowledge of the principles and mech-anisms of animal growth and development. Each contributor has given an authoritativepresentation of the general problems, concepts and lines of investigation of his special topicand illustrated them with selected examples from experimental data.

It will be of interest to all biologists who wish to view the phenomena of development froma perspective which enables them to recognize the great main lines and inner coherence ofthe subject. It will be of special interest to active and future investigators in the experi-mental branches of embryology, pathology, histology, endocrinology and developmentalgenetics.

contributors and contents

JANE M. OPPENHEIMER, Bryn Mawr College-Prob-lems, Concepts, and Their History; Methodsand Techniques

FRANCIS 0. SCHMITT, Massachusetts Institute of Tech-nology-Cell Constitution

H. BuRm STEINBACH, University of Minnesota; andFLORENCE MOOG, Washington University-Cellular

MetabolismHANS RIS, University of Wisconsin-Cell DivisionGERHARD FANKHAUSER, Princeton University-The

Role of Nucleus and CytoplasmCURT STERN, University of California, Berkeley-Gene Action

ALBERT TYLER, California Institute of Technology-Gametogenesis, Fertilization and Partheno-genesis

DONALD P. COSTELLO, University of North Carolina-Cleavage, Blastulation and Gastrulation

JOHANNES HOLTFRETER, University of Rochester; andVIKTOR HAMBURGER, Washington University-Em-bryogenesis of Amphibians

DOROTHEA RUDNICK, Albertus Magnus College-Em-bryogenesis of Teleosts and Birds

RAY L. WATTERSON, Northwestern University-Em-bryogenesis of Selected Invertebrates

DIETRICH BODENSTEIN, Medical Division, Army Medi-cal Center, Maryland-Embryogenesis of Insects

PAUL WEISS, Rockefeller Institute for Medical Re-search, New York-Nervous System (Neuro-genesis)

VICTOR C. TWITTY, Stanford University-VertebrateOrganogenesis of the Eye

C. L. YNTEMA, State University of New York, MedicalCenter at Syracuse University-Vertebrate Or-ganogenesis of Ear and Nose

J. S. NICHOLAS, Yale University-Vertebrate Or-ganogenesis of Limb and Girdle

W. M. COPENHAVER, College of Physicians and Sur-geons, Columbia University-Vertebrate Organo-genesis of Heart, Blood Vessels, Blood andEntodermal Derivatives

R. K. BURNS, Carnegie Institution of Washington andJohns Hopkins University-Vertebrate Organo-genesis of Urogenital System

ISAAC SCHOUR, University of Illinois College of Den-tistry-Vertebrate Organogenesis of the Teeth

MARY E. RAWLES, Johns Hopkins University-Ver-tebrate Organogenesis of Skin and Deriva-tives

EDGAR J. BOELL, Yale University-Energy Ex-change and Enzyme Development duringEmbryogenesis

ALBERT TYLER-Ontogeny of ImmunologicalProperties

BENJAMIN H. WILLIER, Johns Hopkins University-Ontogeny of Endocrine Correlation

NORMAN J. BERRILL, McGill University-The Deter-mination of Size

WILLIAM ETKIN, City College of New York-Meta-morphosis

L. G. BARTH, Columbia University-InvertebrateRegeneration

J. S. NICHOLAs-Vertebrate RegenerationEDGAR ZWILLING, University of Connecticut-Terato-

genesisEdited by BENJAmIN H. WILLIER Professor of Zoology, JohnsHopkins University, Baltimore, kd.; PAUL A. WEiss, Mem-ber, Rockefeller Institute for Medical Research, New York-Formerly Professor of Zoology, University of Chicago; andVIKTOR HAMBURGER, Professor of Zoology, Washington Univer-sity, St. Louis, Mo. About 750 pages, 7" x 10", 248 illustra-tions. Ready in January, 1955.

W. B. SAUNDERS COMPANYWest Washington Square Philadelphia 5

SCIENCE Is published weekly by the AAAS, 1515 Massachusetts Ave., NW, Washington 5, D. C. Entered at the Lancaster, Pa., Post Office as secondclass matter under the act of March 3, 1879. Annual subscriptions: $7.50; foreign postage, outside the Pan-American Union, $1; Canadian poste, 50¢.

1A24 DECEMKBER 1954

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CentennialSymposia presented to commemorate the firsthundred years of AAAS include 42 papersby leading scientists in thirteen major fields:* Sciences of Society * The World's Natural* Educational Potentials Resources* Human Individuality . Genes and Cytoplasm* Food and Nutrition * High Polymers* Housing* World Health Problems' Interactions of matter* Sources of Energy and Radiation* The Upper Atmosphere'Waves and Rhythms

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SCIENCE, VOL. 120

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SCIENCE, VOL. 1204A