When the bookkeeper who made the entries is living and testifies that he made the entries in the usual course of business at the time of the transactions, although he remembers and can testify nothing about the facts recorded in the entry, such entries are of themselves primary evidence of the facts recorded.

Where the bookkeeper, at the time of trial, is not within the jurisdiction of the court, or deceased, or not accessible, upon proof of his handwriting and inaccessibility, the books should be received in evidence. If insane, the above should be supplemented by his conservator's oath.2