Their widespread use in the eighteenth century is due to various causes. In the first place they represent a survival, however artificial and lifeless, of the great mediaeval world of allegory, with its symbolic representation derived from the pagan and classical mythologies, of the attributes of the divine nature, and of the qualities of the human mind, as living entities. But by now the life had departed from them; they were hopelessly effete and had become consciously conventional and fictitious.[247] They also owed their appearance, as indicated above, to more definite literary causes and “fashions”; they swarm especially, for instance, in the odes of the mid-century, the appearance of which was mainly due to the influence of “L’Allegro” and “Il Penseroso.” The virtues and vices, the “shadowy tribes of the mind,” which are there unceasingly invoked and dismissed are mechanical imitations of the figures that the genius of Milton had been able to inspire with real poetic value and life. They play their part similarly and just as mechanically in the didactic and satirical verse characteristic of the period. But whether regarded as a sort of literary flotsam and jetsam, or as one of the symptoms of “Milton-mad” verse, these personifications are nearly all enfeebled by weaknesses inherent in their very genesis. Only a deep and intense conception of a mental abstraction can justify any attempt to personify it poetically; otherwise the inevitable result is a mere rhetorical ornament, which fails because it conveys neither the “vast vagueness” of the abstract, nor any clear-cut pictorial conception of the person. Even with Gray, as with the mere poetasters who used this figure to excess, it has the effect of a dull and wearisome mannerism; only here and there, as in the sonorous lines in which Johnson personified Worth held down by Poverty, does the display of personal emotion give any dignity and depth to the image. Again, the very freedom with which the conventional abstractions are employed, allowing them to be introduced on every possible occasion, tends to render the device absurd, if not ludicrous. For the versifiers seemed to have at their beck and call a whole phantom army upon which they could draw whenever they chose; for them they are veritable gods from the machines. But so mechanical are their entrances and exits that the reader rarely suspects them to be intended for “flesh and blood creations,” though, it may be added, the poetaster himself would be slow to make any such claim. To him they are merely part of his stock-in-trade, like the old extravagances, the “conceits,” and far-fetched similes of the Metaphysical school.