been used in special studies to draw their force from the extra-human sources, instead of draining the vitality of other faculties. At present the Sabbath, so far as it is used at all, is appropriated to the teaching of the special study called " religion " (i.e., the history of the lives and opinions of former synthesizers); and no adequate provision is made for mental acts of synthesis on the part of the pupils themselves. Such synthesis as they are taught to do, is left to chance and to individual teachers. Boole's Text-Book of Differential Equations is, in its way, a model of what can be done, within the compass of a particular subject, towards alternating special study with synthesis. But, within that compass, there is no scope except for time-synthesis (i.e., the study of the History of the subject), which in Boole's book alternates with the study of the subject itself. The book has been superseded; more modern ones serve more effectually the purpose of preparing for Examinations. Gratry has received little attention from ordinary teachers. His splendid analysis of the effects of synthesis alternating with specialization, in giving vitality, is mixed up with details of the special plan of sequence in study by which he secured the alternation for himself. Now Gratry's sequence could not be accurately followed in any school; it could not be attempted in any school which prepared pupils for Examination. Therefore commonplace teachers ignore him altogether, and the course of Natural Selection throws all the benefit of Gratry's discoveries into the hands of teachers who have intellect enough to seize his main idea and disentangle it from his special plans.
So with regard to Boole's text-books. The time-
