HYPERAEMIA OF THE BRAIN AND ITS MEMBRANES. 187 



As a result of illusion, the most harmless things may become objects 

 of great terror to patients suffering from hyperaemia of the brain, par- 

 ticularly to children. Dizziness^ which is one of the most frequent 

 symptoms of hyperaemia of the brain, and of many other cerebral dis- 

 eases, is, as a rule, a simple hallucination, since it consists in a vivid 

 representation of a movement of the body of the patient himself, or of 

 the bodies of surrounding objects which the patients imagine they see 

 or feel, although they are actually at rest. "We shall hereafter speak 

 of other forms of dizziness. Closely related to the symptoms of in- 

 creased mental excitement are sleeplessness and the disturbance of 

 sleep by vivid dreams, symptoms which are very common in hyperae- 

 mia of the brain. 



Among the symptoms of depression observed in the sensibility in 

 cerebral hyperaemia, we must first mention a certain insensitiveness, a 

 tolerance to external irritation, bright light, loud noise, etc. There is 

 no reaction to slight irritation. On an increase of this in complete anaes- 

 thesia to complete cerebral anaesthesia, the patients do not perceive 

 even the severest irritation. The excitability of the portions of the 

 brain through which external impressions are perceived is lost. The 

 motor symptoms of depression are decided slowness and sluggishness 

 in the motions of the patients ; " their limbs are as heavy as lead." 

 If this state increases, there is complete inability to make any volun- 

 tary movement (cerebral paralysis). The excitability of the motor 

 centres is extinguished. The psychical symptoms of depression are : 

 loss of interest, and indifference ; great slowness of thought, and limi- 

 tation of the ideas; inclination to sleep, from which the patient is 

 aroused with difficulty, and subsequently cannot be aroused at all. 

 When this state is increased to the highest point, consciousness is com- 

 pletely lost. 



In hyperaemia of the brain there is not unfrequently, also, a devia- 

 tion from the normal in those movements that are excited by the cere- 

 bral nerves, independently of the will. Thus, in states of irritation the 

 pupil is contracted, because the oculo-motor nerve is more excited ; in 

 depression it is dilated, because then the sympathetic filaments of the 

 iris act more strongly. In the same way, just as, in physiological 

 experiments, increased excitement of the vagus causes the heart to 

 beat slower, while in central paralysis of the vagus, as well as after its 

 division, the heart's action is more frequent. In paralytic states of the 

 brain, respiration is often very slow, deep, and stertorous. Although 

 we cannot give an exact explanation of this symptom, we may still 

 call attention to the fact that, after division of the vagus in animals, 

 besides other symptoms, there is always retardation of the respiration. 

 Lastly, we must mention vomiting as a very frequent and importanl 



