482 PHYSIOLOGY CHAP. 



pornpic hallucinations, according to Myers, are only the perfecting, 

 at the moment when sleep is being dispersed, of the images seen 

 in the dream. In both cases these hallucinations witness to 

 an intensification of internal vision at the extreme phases of 

 sleep, contiguous with waking, due to a state of hyperaesthesia of 

 the cerebral vision, or better, to exaggerated activity of the 

 cortical visual areas, aroused by internal stimuli of unknown 

 character during incomplete sleep. 



Visual hallucinations are common in the waking state among 

 visionaries (such as, to take a classical example, the famous 

 Scandinavian theosophist Swedenborg). They are most frequent 

 in the insane, and form the basis of- their delusions. Even under 

 perfectly normal conditions, there is in the waking state a more 

 or less obvious trace of the power of subjective vision. Every 

 representation, or the evocation in memory of a visual image, 

 suggests a rough draft, which is usually faint, evanescent, and 

 obscure ; sometimes, however, it is so vivid that painters can 

 reproduce from memory the characteristic physiognomy of the 

 people known to them. In " visuals," however, i.e. in certain pre- 

 disposed individuals, these images in the initial and terminal 

 phases of sleep assume the form of perfect hallucinations witli all 

 the characters of real visual images. 



In " auditives," on the contrary, and primarily in musicians, it 

 is the faculty of internal hearing that is specially prominent in 

 sleep. Myers quotes certain cases of this; but the most classical 

 example is the famous " Devil's Sonata " which the violinist 

 Tartini heard in a dream while staying at the Franciscan Convent 

 in Assisi, and partly transcribed, as best he could, on awaking. 

 The French painter Marchal recorded this marvellous musical 

 dream in a much-admired picture in the Gallery at Weimar. 



These hallucinatory images visual or auditory probably, 

 as Myers believed, constitute the highest point that the common 

 sensorial faculties are capable of attaining, and it is remarkable 

 that, normally, it is only reached in sleep. 



The faculty of imagination, memory, and constructive ideal 

 associations are also enhanced in sleep. Myers refers to the 

 "admirable psychological insight" with which Eobert Louis 

 Stevenson described his own experiments in dreaming. 1 " By self- 

 suggestion before sleep Stevenson could secure a visual and 

 dramatic intensity of dream-representation, which furnished him 

 with the motives for some of his most striking romances." 



The well-known inspirator^/ dreams of Condillac, Cardano, 

 Burdach, Lotze, Coleridge, Voltaire, and others arose in the same 

 way. And not only imagination and memory, but also the power 

 of ratiocination, calculation, and argument, may be intensified in 

 dreaming. Cases are known in which problems have been solved 



1 Across the Plains, "A Chapter on Dreams." R. L. Stevenson. 



