230 PHYSICAL EXPRESSION. 



his head from a familiar object, or from the sight 

 of his food, and say, " No, no ; " here the sight of 

 the object, instead of causing a reflex movement of 

 head, eyes, and hands towards the object, moves all 

 from it. The irritability of the nerve-centres is 

 indicated by movements in the opposite direction 

 from that which the same stimulus would produce 

 in health. Besides these reflex signs we find the 

 voice altered when spoken to he may answer 

 sharply; the kinetic force generally is lessened 

 and irregular in kind; twitching irregular move- 

 ments are not uncommon. The nervous children 

 described in chap. vii. often show marked signs of 

 irritability. The spontaneous postures assumed are 

 those of fatigue, with the addition of slight irregular 

 twitching movements. If this condition lasts long 

 trophic signs are usually seen, nutrition is lowered, 

 and wasting occurs. It is not convenient here to 

 discuss the relation of such trophic changes to the 

 motor phenomena of irritability, but let me refer 

 the reader again to chap, vii., p. 113, where some ex- 

 periments upon the sensitive plant are described. 

 Abnormal conditions in the body, particularly in 

 the abdomen, may render the subject irritable; so 

 may fever, gout, etc. 



Nutrition is a matter of the highest importance. 

 We must consider its expression. I am, however, 

 unwilling to enter at any length upon the expres- 

 sion of nutrition in this volume, because the subject 

 is so extensive and so important ; in fact, the whole 

 of this volume is preparatory to an attempt to 

 gain knowledge upon the subjects nutrition, and 





