But no critical theory can hold a work of imagination to a strict account. You may clap John Locke into the witness-box and riddle him with cross-questions: the same court has no authority to put a poet on oath to justify himself in every line; he is satisfied to let the drift of his thought be traced through the material in which he works. Quartz that is found in certain localities is as good as gold, and rewards us for suspecting it. We need not strain Shakspeare's page into too minute an adaptation to our views in order to avoid rejecting it. If he convinces us that Macbeth and his wife have composed the tragedy before his pen touches the paper, the witches may appear just what we and Macbeth choose to have them,--at one moment concocters of country spells to give him a drench of murder, at another moment concocted themselves by a spell which his soul has brewed. This spiritual gift is the main cause of all his practical hesitations. His strongest passion discharges and exhausts itself in a pulse of fantasy; as the electric fish lies awhile torpid after the transmission of a shock. In his case, there is imperfect connection of the motor nerves that run between imagining and doing; so that his milk of human kindness has time to mingle with his mood. When his wife has grown sick and incompetent to stimulate, dire necessity alone can do it for him; as we see after he has had the vision of Banquo's line of kings, when somebody informs him that Macduff, his most formidable enemy, has fled. This is his self-chiding:-- "Time, thou anticipat'st my dread exploits: The flighty purpose never is o'ertook, Unless the deed go with it. But no more sights." Macduff's "wife, children, servants, all that could be found," are slaughtered by him. It is a deed that, making his fortunes more impaired than ever, betrays to us how feverish and impolitic his course becomes. Far better for him if he had not let the desperate crisis of his fate drive him out of the land of dreams. Shakspeare lets us hear Macbeth chiding the brag of his imagination when he says, "But no more sights." He has had enough of them,--too much time wasted in those presentiments which never have the element of prevention. On the contrary, it is a common experience that something is so sure to happen that it can impart to us a fruitless forefeeling of itself, as Henry IV. felt the blade of Ravaillac in his side a week before it struck him. Macbeth will humor no more sights. That is the key to Shakspeare's conception of the character. We are to understand that henceforth Macbeth is cured of his hallucinations.