What is the test for the purpose of bringing an action against the directors of a corporation for negligence and wrongful performance of their duties as directors?

It is very clear, therefore, that we are committed by our decision in O'Brien v. Fitzgerald to the view that where the action is to hold persons responsible to the receiver of a corporation for a neglectful and wrongful performance of their duties as directors, and to recover the losses sustained by the corporation, the action is one at law, and that something more [154 N.Y. 490]is required to warrant the intervention of a court of equity than mere allegations showing that the acts complained of are numerous and complicated; that they are difficult of ascertainment, without a discovery with respect to them; and that a multiplicity of actions would be necessary if all the directors who were in office during the whole or a part of the time within which the acts complained of were committed could not be associated as defendants in one action.