Rife himself did studies, and his results are in the Spooky2 database, in the one labeled RIFE. He had optical microscopes and could observe the effect of frequency on bacteria and cancer cells.
When Rife was shut down by mainstream medicine, they destroyed his optical microscopes, so even today the microscopes are not as good as his, that is, to observe living samples.
There is electron microscopy, that can view things even smaller, but it operates only on dead things, not living cells or bacteria. So there is no means for people to do these studies.
The other issue is that the people who funds almost all research have no interest in finding a solution like Rife's, because there is no money in that solution.
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