&LASS IV. 1. 1. OF ASSOCIATION. 



Thus when vomiting occurs with cold extremities, a blister on 

 the back in a few hours occasions universal warmth of the skin, 

 and stops the vomiting. And when a diarrhoea occurs with pale 

 skin and cold extremities, the pricking of the points of a flannel 

 shirt, worn next the skin, occasions universal warmth of it, and 

 checks or cures the diarrhoea. 



In some associate trains of action, nevertheless, reverse sym- 

 pathies more frequently occur than direct ones, and in others di- 

 rect ones more frequently than reverse ones. Thus in continued 

 fever with debility, there appears to be a reverse sympathy be- 

 tween the capillary vessels of the stomach and those of the skin; 

 because there exists a total aversion to solid food, and constant 

 heat on the surface of the body. Yet these two systems of ves- 

 sels are at other times actuated by direct sympathy, as when pale- 

 ness attends sickness, or cold feet induces indigestion. This sub- 

 ject requires to be further investigated, as it probably depends 

 not only on the present or previous plus or minus of the sensorial 

 power of association, but also on the introduction of other kinds 

 of sensorial power, as in Class IV. 1. 1, D.; or the increased 

 production of it in the brain, or the greater mobility of one part 

 of a train of actions than another. 



Thus when much food or wine is taken into the stomach, if 

 there be no superfluity of sensorial power in the system, that is, 

 none to be spared from the continual actions of it, a paleness and 

 chilness succeed for a time; because now the expenditure of it 

 by the increased actions of the stomach is greater than the present 

 production of it. In a little time, however, the stimulus of the 

 food and wine increases the production of sensorial power in the 

 brain, and this produces a superfluity of it in the system; in con- 

 sequence of which, the skin now becomes warm and florid, 

 which was at first cold and pale; and thus the reverse sympathy 

 is shortly converted into a direct one; which is probably owing 

 to the introduction of a second sensorial power, that of pleasur- 

 able sensation. 



On the contrary, when an emetic drug produces sickness, the 

 skin is at first pale for a time by direct sympathy with the capil- 

 laries of the stomach; but in a few minutes, by the accumulation 

 of sensorial power in the stomach during its less active state in 

 sickness, the capillaries of the skin, which are associated with 

 tkose of the stomach, act with greater energy by reverse sympa- 

 thy, and a florid colour returns. Where the quantity of action is 

 diminished in the first part of a train of motions, whether by pre- 

 vious diminution of sensorial power, or present diminution of 

 stimulus, the second part of the train becomes torpid by direct 

 sympathy. And when the quantity of action of the first part 



