"x x x.
The general evidentiary rule is that evidence that one did or did not do a certain thing at one time is not admissible to prove that one did or did not do the same or a similar thing at another time. However, evidence of similar acts may be received to prove a specific intent or knowledge, identity, plan system, scheme, habit, custom or usage and the like. “The rule is founded upon reason, public policy, justice and judicial convenience. The fact that a person has committed the same or similar acts at some prior time affords, as a general rule, no logical guaranty that he committed the act in question. This is so because, subjectively, a man's mind and even his modes of life may change; and, objectively, the conditions under which he may find himself at a given time may likewise change and thus induce him to act in a different way. Besides, if evidence of similar acts are to be invariably admitted, they will give rise to a multiplicity of collateral issues and will subject the defendant to surprise as well as confuse the court and prolong the trial. Evidence of similar acts may frequently become relevant, especially to actions based on fraud and deceit, because it sheds light on the state of mind or knowledge of a person; it provides insight into such person's motive or intent; it uncovers a scheme, design or plan, or it reveals a mistake.
x x x."
