The distinguishing feature of early Mahometan tradition is, that it was essentially oral. Even if committed to writing, the tradition acquired no new authority from the record : it must still be transmitted by word of mouth, the record counting absolutely for nothing. The canons of tradition formed a distinct science, and had a literature of their own. It was found necessary to relax the strict Mahometan law of evidence in its application to tradition: thus, a single credible witness (instead of the legal two) sufficed, if only the links of oral transmission were otherwise complete. An exception was also made in favour of epistolary communications, which at a very early period were admitted as trustworthy without oral attestation; but under all other circumstances, the test by word of mouth was rigidly insisted upon, as essential to the validity of each step in the transmission. Thus the possessor of the notes or memoranda of a Sheikh could make no recognised use of them unless he was able to say that they had been orally vouched for by the writer of the manuscript; and indeed the entire rehearsal of each tradition by the person transmitting and the person receiving it, in the hearing of each other, was insisted upon as an indispensable condition of trustworthiness. 

Where the traditions of a Companion were handed down in various channels, we have special means of testing the accuracy of transmission. Thus Abu Horeira had 800 pupils to whom he communicated his learning, several of whose names survive in the traditional chains; now, since some of these lived at a period when it was customary to commit a tradition to writing, hence, by comparing the text of the same tradition as given by the different authorities, we have a strong guarantee that the words of Abu Horeira himself have been correctly preserved. But the same cannot be said of most of the Companions of the Prophet who were the youngest and survived the longest. There was among them great latitude for fabrication. A collector of tradition often stood in a specially intimate relation to some one of the Companions (as Orwa to Ayesha, Ikrima to the son of Abbâs, Abu Ishâc to Barâ), and became thus the chief and often sole medium for transmitting the traditions of the Companion to whom he was thus attached. Such monopoly was no doubt often greatly