Marsh, Crane, and Bateson (defendants) worked together to sell the use of electric machines to the sick that the defendants claimed could cure almost any ailment. The defendants charged between $175 and $2,000 for the use of the machines. The machines were actually identical to devices used commonly for radio and TV repair that retailed for less than $50. Undercover agents with the Food and Drug Administration investigated the defendants and recorded the defendants making such representations. The agents also observed the defendants taking the money. The State of California (plaintiff) charged the defendants with theft by false pretenses. The defendants attempted to introduce proof that the defendants relied on certain reports by doctors and scientists and reasonably believed that the machines did actually provide a medical cure. The trial court permitted the defendants to testify that the defendants relied on such reports but did not allow the content of the reports to be introduced as evidence. The defendants also presented 15 witnesses who testified that they had been cured by the machines. The jury convicted the defendants, and they appealed.