century, prepared a harmony of the four gospels—­the Gospel by four, as Eusebius calls it.  His plan was, to arrange in the order of Matthew the parallel passages side by side, interpolating those that were wanting in Matthew.  To this end, he divided each of the gospels into sections the length of which was very various, being wholly determined by the parallelisms of the other gospels.  Of these sections Matthew contained 355; Mark, 234 (in Wordsworth’s Greek Testament, 236 are given); Luke, 342; John, 231 (in Wordsworth’s Greek Testament, 232).  The infelicity of this arrangement was that, with the exception of the first gospel, the true order of the evangelists was broken up—­“The train of sequence of the three was destroyed in respect to the orderly course of reading,” as Eusebius says (Letter to Carpianus, given in Wordsworth’s Greek Testament).

To remedy this evil, Eusebius, bishop of Caesarea, in the following century connected with these Ammonian sections his ten canons.  These are ten tables, arranged according to the order of Matthew, or where sections are wanting in Matthew, according to the order of the next evangelist that contains them, in such a way as to show at a glance what sections of the other evangelists answer to any given section of that gospel which stands first in order in each canon.

    Numbering the four gospels in order—­1, 2, 3, 4—­the ten canons
    of Eusebius contain as follows: 

        I. Sections common to 1, 2, 3, 4. 
       II. " 1, 2, 3. 
      III. " 1, 3, 4. 
       IV. " 1, 2, 4. 
        V. " 1, 3. 
       VI. " 1, 2. 
      VII. " 1, 4. 
     VIII. " 2, 3. 
       IX. " 3, 4. 
        X. Sections peculiar to one.

A couple of examples will make this matter plain.  Turning to what is now the beginning of the thirteenth chapter of Matthew, we find (the Greek numerals being exchanged for those in common use) the sign 131/II that is, the 131st Ammonian section of Matthew with the second canon of Eusebius.  Turning to the table of the second canon, we find, corresponding to the 131st section of Matthew, the 36th of Mark and the 76th of Luke, which contain the parallel passages concerning the sower.  Again, connected with Mark 1:23, is the sign, 14/VIII whence we learn, by reference to the eighth canon, that the fourteenth section of Mark answers to the 25th of Luke.  By a repetition of the canons as often as necessary, so as to allow each gospel in turn to take the lead, Wordsworth has greatly facilitated the work of comparing parallel passages.

“The Codex Vaticanus B, contains a distribution into sections wholly peculiar.  Of these, St. Matthew contains 170, St. Mark 61, etc.  The length of these divisions is very