1954 John Enders developed what would become the Gold Standard for "Virus Isolation". Problem was in his own paper he inadvertently conducted a control with an Uninfected culture which in his own words produced CPE that could not be distinguished from the infected culture.

In his following sentence he says that once he further treated them with chemicals they "Could be distinguished" which is irrelevant. Any observable effect (CPE) found in a NEGATIVE Control (I.e a control where the observable effect should NOT be seen) is classed as a failure and the method should be junked. Instead it was adopted by the establishment as the gold standard and the fraud has perpetuated ever since.