108 



somewhat less pronounced degree, were recognized ; these virtually 

 disappeared in a few minutes. 

 In one dream systolic pressure rose from 130 to over 200 



Emotion, Motor Effort, and Gastro-intestinal 

 Disturbance. 



While the most striking cardio-vascular effects are 

 naturally present in dreams with a strong emotional con- 

 tent, it is to be noted that a vivid dream of active move- 

 ment (cycling, for example) without sensations of night- 

 mare, etc., may cause a pronounced rise of blood pressure. 

 Thus in an instance of this kind the pulse tension was 

 greatly increased and the pulse pressure was extensive while 

 the heart rate remained at 72-75 ; the elevation of blood 

 pressure was evidently brought about mainly by vaso- 

 constriction. 



It is noteworthy that the amount of disturbance (circula- 

 tory, respiratory, etc.) associated with vivid and alarming 

 dreams varies greatly in different individuals and even in 

 the same individual under different conditions ; the effects 

 are sometimes remarkably slight in the case of dreams that 

 are at other times attended by very pronounced effects of 

 the kinds described above. There is reason to believe that 

 the presence of some gastro-intestinal disturbance at the 

 time may sometimes play a part in facilitating the 

 development of the more marked effects on circulation, 

 respiration, etc. 



Dangers of the Circulatory Disturhanres. 

 These cardio-vascular changes, involving sudden demands 

 on the heart's power with great alterations in its rate and 

 force and a steep and sometimes very extensive rise in 

 blood pressure, are quite harmless in the healthy individual. 

 Vivid dreams, involving hurrying to catch trains, etc., with 

 failure to do so, are common in many persons and sometimes 

 persistently recurrent — with no injurious consequences 

 apparently. But the case is obviously very much otherwise 

 with a damaged vascular system, life going on under con- 

 ditions which afford only a narrow margin of safety. There 

 may be a myocardium abnormal in certain functional 

 respects, whether or not these be attended by recognizable 

 structural alterations with or without obvious coronary 

 lesions, giving a susceptibility to ventricular fibrillation, or, 

 on the other hand, a defective arterial tree with localized 

 weakenings (by miliary aneurysms, etc.) in the brain vessels, 

 tuberculous damage in the lungs, ulcerative conditions in 

 the gastro-intestinal tract, etc., where haemorrhage may 

 readily be determined. In a heart susceptible to fibrillation 

 a sudden call on the heart during muscular exertion and 

 excitement in the waking state is often fatal ; in the dis- 

 turbed conditions of sleep and dreaming a similar mechanism 

 is sometimes brought suddenly and strongly into action — 

 diminution of vagus control and, especially under emotional 



