Smithsonian Report. 1962. — Russell 



Plate 4 



1. A soil phage, which destroys bacteria. Phages are a class of viruses; they consist of 

 DNA surrounded by a protein covering, and they are capable of multiplying. (Electron- 

 micrograph by E. \'an Slogteren.) 



"^^ 



B. hyacinihi, a soil bacterium. (Electron-micrograj,.. 



