126 



THE PHYSICS OF VIRUSES 



a maximum at 0.007J/, of CaCh at 0.02J/, and of KCl at 

 0.02 J/ concentrations. They associated this with the adsorption 

 process. Puck, Garen, and Cline then investigated the rate con- 

 stant for the attachment of T-1 as a function of the salt con- 

 centration for NaCl and CaClo. Their results are shown in Fig. 



200- 



o 



< 100 



10" 10' 



Salt Molarity 



10 



Fig. 5.1. Variation of the velocity constant for attachment of T-1 phage to 

 E. coli with salt concentration, as measured by Puck, Garen, and Cline 

 (1951). These results show the strong effect of the ions in the medium on the 

 attachment. 



5.1. There is a rapid rise in attachment for the divalent ions and 

 a similar rise at higher concentration for monovalent ions. Excess 

 of either kind of ion diminishes the attachment. 



Further experiments showed that there is no lag period fol- 

 lowing the addition of divalent ions. The rapid attachment 

 of virus is very striking in such a case. Also the reaction con- 

 stant, while increasing from 2° C to a maximum at 37° C, does 



