PREFACE  TO  FOURTH  EDITION

It  is  a  satisfaction,  after  six  years  of  exposure  to
criticism,  not  to  feel  constrained  to  unsay  anything
that  was  said  in  the  first  edition  of  these  pages.
Alterations  from  previous  edition  of  greater  or  less
importance  are  to  be  found  on  pages  3,  4,  16,  17,  19,  27,
28,  29,  31,  33,  36,  40,  45,  113,  128,  129,  132,  and  161.
Boston,  January,  igi6.  C.  B.  F.