CHEMISTRY AND VIRAL GROWTH 



A. D. HERSHEY, Department of Genetics, Carnegie Institution of 

 Washington, Cold Spring Harbor, New York 



Introduction 



The points of contact between biochemistry and the central 

 mysteries of biology — meaning here the reproduction and func- 

 tioning of hypothetical determinants of heredity — are necessar- 

 ily few (3). In recent years the study of viruses has emerged as 

 one of them, important if only because of its relative isolation. 



Work by many investigators with many different viruses has 

 contributed to this development, not always in tangible ways. 

 It would be difficult, and perhaps not at present very rewarding, 

 to trace this genealogy. Even the work with bacterial viruses has 

 recently split into two parts calling for separate review (5,45). 

 In this discussion I shall focus attention on what happens when 

 bacteriophage T2 infects the common intestinal bacterium, 

 Escherichia coli. 



The Reproductive Cycle 



Morphological, biochemical, and genetic studies have re- 

 vealed a developmental cycle that can be represented very 

 simply. Figure 1 names the recognized stages and processes. 

 The basic information from which this cycle has been deduced 

 may be summarized as follows. 



