Procedure: 

(i) Hershey and Chase grew some bacteriophages on a medium that contained radioactive phosphorus (³²P) and some in another medium with radioactive sulphur (³⁵S). 

(ii) Bacteriophages grown in the medium containing radioactive phosphorus (³²P) contained radioactive DNA.

(iii) Similarly bacteriophages grown in the medium containing radioactive sulphur (³⁵S) contained radioactive protein. 

(iv) Both the radioactive bacteriophage types were allowed to infect E. coli separately. 

(v) Soon after infection, the bacterial cells were gently agitated in blender to remove viral coats. 

(vi) The culture was also centrifuged to separate the bacteriophage particle from the bacterial cell. 

Observations and Conclusions: 

(i) Only radioactive ³²P was found to be associated with the bacterial cell, whereas radioactive ³⁵S was only found in surrounding medium and not in the bacterial cell. 

(ii) This indicates that only DNA and not protein coat entered the bacterial cell. 

(iii) This proves that DNA is the genetic material which is passed from virus to bacteria and not protein.