"What, then, is the essential nature of an affidavit? It does seem to me that the essential nature of an affidavit is that it is evidence which is not only given by a deponent but which the deponent has not only stated to be true but has sworn to be true. That, indeed, is, no doubt, the origin of the word "affidavit" which, coming from a Latin expression which incorporates the idea of an oath, refers to swearing that the statement is true. The practice on taking an oath in respect of an affidavit is that the deponent has to appear in person before a Commissioner for Oaths and swear on the Bible or other holy book in front of the Commissioner for Oaths that the affidavit is true."