16 VIRUSES 





Pi 





 / • -^ 



FIGURE 15 - ELECTROK MICROGRAPH OF THE T^ BACTERIA 

 OF E. COLI. ID. G.Sharp et.al., Proc . Soc. Exp. Biol. 

 & lied. 61, 259 1 1946) J. 



These purified preparations of viruses are the only sensihle starting materials 

 for many types of experiments designed to discover the nature of viruses. All 

 of them were obtained by the application of physical and chemical procedures. 

 The development of these procedures was an outgrowth of the concept that viruses 

 are molecules. Thus, this concept has served the cause of virology magnifi- 

 cently. What matters it whether the concept is right or wrong? 



