BY the time that a theological treatise has, without any undue haste, advanced to the stage of a second edition its author is often disposed to feel that he would like to write it all over again. He sees his work as it is, and as it ought to be; and he dreams of the manner in which he might improve it if he lived in a golden age wherein publishers could afford to encourage their clients in luxurious schemes and costly adventures. There is comfort, however, in the re?ection that a book which has once been constructed with care is not always the better for being recomposed. In the case of the present volume, also, I am the more content to abstain from extensive changes in that I have not seen reason to depart from any of the positions maintained, or to alter expositions, or to cancel criticisms. A thorough revision has of course been made; references have been verified, typographical errors removed, some expressions amended and some statements modified. Out of respect, further, to those authorities who have been good enough to favour me with comments and discussions, and in view of knowledge acquired since this volume was first issued, it is desirable to preface the present edition with one or two explanations.