Look up royal rife and rife machine, if you ever get a chance to see and use one of his surviving microscopes they are things of beauty and science first live cell obeservation.
The argument over frequency and it’s uses is also continued in a different way, used by John Hutchinson, both have been discredited, but I have first hand seen hutchinson do some amazing things with frequency. There is an effect named after him. The third frequency person is tesla. Lots to read.and try to wrap your mind around things that some of the most brilliant people have just started to un wrap