The evidence of those who relate, not what they know themselves, but what they have heard from others. 2. As a general rule, hearsay evidence of a fact is not admissible. If any fact is to be substantiated against a person, it ought to be proved in his presence by the testimony of a witness sworn or affirmed to speak the truth. 3. There are, however, exceptions to the rule. 1. Hearsay is admissible when it is introduced, not as a medium of proof in order to establish a distinct fact, but as being in itself a part of the transaction in question, when it is a part of the res gestae. 4. 2. What a witness swore on a former trial, between the same parties, and where the same point was in issue as in the second action, and he is since dead, what he swore to is in general, evidence. 5. 3. The dying declarations of a person who has received a mortal injury, as to the fact itself, and the party by whom it was committed, are good evidence under certain circumstances. 6. 4. In questions concerning public rights, common reputation is admitted to be evidence. 7. 5. The declarations of deceased persons in cases where they appear to have been made against their interest, have been admitted. 8. 6. Declarations in cases of birth and pedigree are also to be received in evidence. 9. 7. Boundaries may be proved by hearsay evidence, but, it seems, it must amount to common tradition or repute.