It is scarcely necessary to refer to the occasional creative activity of men of genius during actual sleep or to the debts which they have acknowledged to suggestions received in dreams.[268] This has perhaps, indeed, been more often exaggerated than overlooked. There can be no doubt that a great many writers and thinkers, including some of the highest eminence, have sometimes been indebted to their dreams. We might expect as much, for most people occasionally have more or less vivid or suggestive new ideas in dreams,[269] and it is natural that this should occur more often, and to a higher degree, in persons of unusual intellectual force and activity. But it is more doubtful whether the creative activity of normal dreams ever reaches a sufficient perfection to take, as it stands, a very high place in a master's work. Coleridge's 'Kubla Khan' has the most notable claim to be an exception to this rule. This poem was written by Coleridge in 1788, soon after 'Christabel,' and at a time when the poet was suffering much from depression, and taking a great deal of laudanum. We are entitled to assume, therefore, that the poem was composed under the influence of opium, and not in normal sleep. It may be added that it is difficult to believe that Coleridge could have recalled the whole poem from either a normal or abnormal dream; as a rule, when we compose verses in sleep we can usually recall only the last two, or at most four, lines.[270] Moreover, there is reason to believe that the first draft of 'Kubla Khan' was not the poem as we now know it.[271] After Coleridge's 'Kubla Khan' the most important artistic composition usually assigned to a dream is the _Trillo del Diavolo_ sonata of Tartini, the eighteenth-century composer and violinist, who has been called the prototype of Paganini. Tartini, who was a man of nervous and emotional temperament, seems to have possessed real genius, and this sonata is his principal work. But there is not the slightest ground for stating that it was composed in a dream, and Tartini himself made no such claim.[272]