180 



THE PHYSICS OF VIRUSES 



the former which has been traced by Hershey and Chase. Prob- 

 ably the inner protein layers are more tightly bound to the nu- 

 cleic acid and go with it into the bacterium. Strong, specifically 

 distributed charges must exist at the point of attachment, and 



600 A- 



Coating of protein 

 carrying antigenic nature 



Nucleic odd 



Enzyme for entry 



Specific charge 



Fig. 7.4. Schematic drawing of T-2 phage based on osmotic shock and radio- 

 active studies. The phage attaches by the tail, enzymatically digests an open- 

 ing in the bacterium, releases its nucleic acid, and leaves the protein coat 

 outside. 



the enzyme which takes over after the electrical attachment 

 phase must also be located near there. 



Some very interesting thoughts follow from this picture. If 

 attachment is at the tail, as this picture suggests, then the fact 

 that attachment occurs at every collision, as shown by Schles- 



