GENERAL SENSATIONS. 549 



a castor-oil bottle, which, in itself, is not ugly, " I can't bear to 

 look at it ; the very thought of it makes me feel sick.-" 



However, even without any participation of the mental func- 

 tions, unavoidable nausea may come on from irregular motion, 

 as that of a ship, which often causes nausea in those unaccus- 

 tomed to the sea. Certain conditions of the blood flowing 

 through the nerve centres also cause nausea, as when emetics are 

 injected into the blood. 



Giddiness, which consists in a feeling of inability to keep the 

 normal balance, is often produced in connection with the last by 

 irregular movements, but more surely by a rotatory motion of the 

 body. Other afferent influences may give rise to it, viz., from the 

 stomach, in some cases of irritation ; from the eye, when we look 

 from a height; from the semicircular canals of the ear, by rota- 

 tion of the body ; and also from conditions of the blood, as in 

 alcoholic toxaemia. 



Shivering is also the result of a peculiar nervous effect pro- 

 duced by afferent influences of an unpleasant kind, the sudden 

 application of cold to the skin, a revolting sight, a shrill noise, 

 an intensely nasty taste, and a very shocking narrative may 

 excite a nervous condition, which makes us shiver. 



Titillation follows light stimulation of certain parts of the 

 cutaneous surfaces. It is a peculiar general sensation, in moder- 

 ation not disagreeable, and usually accompanied by a tendency 

 to meaningless laughter or reflex movements. 



