Courts are seldom embarrassed in modern times by the poverty of their resources. On the contrary, with the multiplication of "substantive law" formulae and of new procedural devices, their difficulties more often result from the embarrassment of overwhelming riches. This statement may be best illustrated by a brief review of the equitable devices for achieving preferences and priorities, which have developed so rapidly within the last fifty years and have surmounted almost completely the artificial barriers of legal doctrine. In this field the chief effort of the courts must now be not to develop new machinery, but to reexamine the purposes toward which existing machinery has been directed.