Harshy and Chase (1952) established that DNA is transferred from viruses that infect bacteria. In their experiment, bacteriophage were used. They grew some phages on a medium that contained radioactive phosphorus and some others on medium containing radioactive sulphur. Phages grown in the presence of radioactive phosphorus contained radioactive DNA, but not radioactive protein because DNA contains phosphorus, but protein does not. In the same way, phages grown on radioactive sulphur contained radioactive protein, but not radioactive DNA because DNA does not contain sulphur. Radioactive phages were allowed to attach to E. coli bacteria. As the infection proceeded, virus coats were removed from the bacteria by agitating them in a blender. The virus particles were separated from the bacteria by spinning them a centrifuge.