Hershey and Chase produced a stronger validation that DNA, not protein, was the material carrying hereditary information than Avery, MacLeod & McCarty.
Hershey and Chase showed that phage with either radio-labeled DNA or with a radio labeled amino acid protein coat injected only their DNA into the bacteria, not their protein coat.
The tagged protein coat was left outside the bacteria and agitation readily dislodged this tagged factor from the bacteria's surface also removing the radiolabelling. However the tagged DNA was sufficient to enter the cell and cause it to produce more phage. Due to semi-conservative DNA replication labeled DNA could then be found in some phage leaving the cell after infection.