Introduction＆R．LEE CLARK 1
STRUCTURE OF VIRUSES 5
A Comparative Study of the Structures of a Variety of Bacteriophage Particles with Some Observations on the Mechanism of Nucleic Acid Injection＆DESMOND KAY 7
Structure and Assembly of Regular Virus Particles＆D．L．D．CASPAR and A．KLUG 27
Electron Microscope Studies on the Structure and Symmetry of Virus Particles＆R．W．HORNE 40
Icosahedral Viruses—A Geometric Approach to Their Maturation＆HEATHER DONALD MAYOR 63
Morphology of the RNA Phage FH5＆J．HUPPERT，ANTOINETTE RYTER，and JEANNE FOUACE 68
The Arthropod Viruses＆KENNETH M．SMITH 72
Studies on the Structure of the Mammary Tumor-Inducing Virus(Bittner)and of Leukemia Virus(Gross)＆L．DMOCHOWSKI，C．E．GREY，F．PADGETT，and J．A．SYKES 85
Structure and Genetic Properties of Bacterial Viruses＆THOMAS F．ANDERSON 122
Virus Particles of Mouse Lymphomas and Mammary Carcinoma＆R．KINOSITA and T．KAKEFUDA 141
REPLICATION OF VIRUSES：BIOCHEMISTRY OF VIRUS-INFECTED CELLS 149
Influence of Phages on the Synthesis of Host Enzymes of Bacteria＆MICHAEL B．YARMOLINSKY 151
The Functions of the RNA of Bacteriophage f2＆NORTON D．ZINDER 173
Substances Produced During Replication of Plant Viruses＆ROY MARKHAM 180
Biosynthesis of Viral Ribonucleic Acids＆M．HOMMA，A．V．RAKE，W．PARANCHYCH，D．B．ELLIS，and A．F．GRAHAM 191
The Programing of Herpes Virus Multiplication in Mammalian Cells＆BERNARD ROIZMAN 205
Studies of Replication and Properties of the Bittner Virus＆DAN H．MOORE and MICHAEL J．LYONS 224
VIRAL NUCLEIC ACID：PROPERTIES AND MODE OF REPLICATION 243
Viral Nucleic Acid：Properties and Mode of Replication．Introduction＆W．M．STANLEY 245
Replication of the Nucleic Acids of the Bacterial Viruses＆ROBERT L．SINSHEIMER 246
Biosynthesis of Infectious Ribonucleic Acid of Tobacco Mosaic Virus by Extracts of Healthy Plants＆GEORGE W．COCHRAN 252
Properties of the DNA of Polyoma Virus＆RENATO DULBECCO 271
Early Events in the Reproduction Cycle of Animal Viruses＆P．HAUSEN，H．HAUSEN，R．ROTT，C．SCHOLTISSEK，and W．SCH？FER 282
Early Changes Following Virus Infection：Thymidine Kinase Induction in Cells Infected with Vaccinia and Herpes Simplex Viruses＆SAUL KIT 296
Changes in RNA and Protein Synthesis in Mammalian Cells Infected with a Virulent Virus＆RICHARD M．FRANKLIN and DAVID BALTIMORE 310
AVIAN VIRUSES AND NEOPLASIA 327
Avian Viruses and Neoplasia：Introduction＆W．R．BRYAN 329
Biological and Structural Properties of Rous Sarcoma Viruses＆R．J．C．HARRIS 331
Studies on the Biological，Biochemical，and Biophysical Properties of Avian Tumor Viruses＆J．W．BEARD，R．A．BONAR，URSULA HEINE，GUY DE THé，and DOROTHY BEARD 344
The Infection of Chicken Fibroblast Cultures by Avian Myeloblastosis Virus＆PETER K．VOGT 374
Induction of Differentiation in Certain Target Cells by Avian Myeloblastosis Virus：An In Vitro Study＆M．A．BALUDA，I．E．GOETZ，and S．OHNO 387
BERTNER FOUNDATION LECTURE 401
Properties of a Virus Isolated from Leukemic Mice，Inducing Various Forms of Leukemia and Lymphomas in Mice and Rats＆LUDWIK GROSS 403
VIRUSES AND INTERFERON 427
Viruses and Interferon：Introduction＆W．HENLE 429
Interference and Cell Division＆KURT PAUCKER 430
The Effect of Interferon on the Synthesis of Viral Nucleic Acid＆ROYCE Z．LOCKART，JR．，and T．SREEVALSAN 447
Interference and Interferon in Relation to Tumor Viruses and Tumor Cells＆A．C．ALLISON 462
BIOLOGICAL ASPECTS OF TUMOR INDUCTION BY VIRUSES 485
The Interaction of Polyoma Virus with Hamster Fibroblasts＆MICHAEL STOKER 487
The Role of the Mammary Tumor Virus in Mouse Mammary Noduligenesis and Tumorigenesis＆K．B．DEOME 498
Significance of the Absence of Infectious Virus in Virus-Induced Tumors＆H．RUBIN and H．HANAFUSA 508
INTERRELATIONSHIP OF VIRUSES：INTRACELLULAR AND EXTRACELLULAR FACTORS IN NEOPLASIA 527
The Possible Role of a＂Transmissible Factor＂in Leukemia Induction by Radiation Plus Urethan＆I．BERENBLUM 529
The Combined Action of Viruses and Other Carcinogens＆M．H．SALAMAN，K．E．K．ROWSON，F．J．C．ROE，J．K．BALL，J．J．HARVEY，and G．DE BENEDICTIS 544
Studies on the Oncogenicity of Human Adenovirus＆JOHN J．TRENTIN，YOSHIRO YABE，and GRANT TAYLOR 559
Observations on a Specific Adenovirus 12 Antigen in Virus-Free Adenovirus Tumor Transplants＆R．J．HUEBNER，W．P．ROWE，and L．D．BERMAN 564
Lymphoma in ICR Mice Treated with 4-Nitroquinoline N-Oxide (4-NQO)＆R．KINOSITA and T．TANAKA 571
＂Newer＂and＂Older＂Viruses in Mammalian Malignancy＆MAURICE R．HILLEMAN 580
A Children＇s Cancer Dependent on Environment＆DENIS BURKITT 615
The Role of Viruses in Relation to Cancer in Animals and Man＆FRANK L．HORSFALL，JR． 630
Index 643