Perhaps another reason why these themes have not been utilized in poetry is because they are too fantastic, too bizarre. They lack the proportion and sense of artistic harmony that poetry requires. Strangeness and wonder are true elements of poetry, and magic is an element of the greatest art, but in solution as it were, not in the form observed in science. The miracles of the laboratory are too abrupt, too inconceivable save by intellectual analysis, and present too great a strain upon the powers of the imagination. They are fantastic, while true poetry is concerned with the fancy. Magic and wonder in verse must come from concepts that steal upon the imagination and make appeal through the emotions. Thus some forms of supernaturalism are admirably adapted to the province of poetry, such as the presence of spirits, visitations of angels or demons, ancient witchcraft, and so forth. The elements that have universal appeal through the sense of the supernatural move us in poetry, but the isolated instances, the peculiar problems that occur in scientific research if transferred to poetry would leave us cold. Yet they may come to be used in the next _vers libre_. Nor do these situations come over into the drama save in rare instances. Theodore Dreiser, in a recent volume, _Plays of the Natural and the Supernatural_, makes use of certain motifs that are striking and modern, as[209] where a physician goes on the operating-table, the _dramatis personæ_ including Demyaphon (Nitrous Acid), and Alcepheron (a Power of Physics), as well as several Shadows, mysterious personages of vagueness. These Shadows here, as in _The Blue Sphere_, are not altogether clear as to motivation, yet they seem to stand for Fate interference in human destiny. In the latter play Fate is also represented by a Fast Mail which is one of the active characters, menacing and destroying a child. [209] In _Laughing Gas_.