230 RELATIONS OF THE VASCULAR FACTORS. [BOOK i. 



the calibre of the blood-vessels in other parts. This distant reflex 

 change may be of the same or the opposite nature as the local 

 change. 



7. By reflex action to a quickening or slowing of the heart's 

 beat, though the heart is in this respect less intimately connected 

 with the skin than with other parts. 



Out of these primary effects there may arise secondary effects ; 

 the constriction or dilation produced locally will affect the general 

 blood-pressure, which in turn will produce all its effects. 



The modifications of the heart-beat will not only affect the general 

 blood-pressure, but in a reflex manner may affect the peripheral 

 resistance, and hence the flow of blood in particular areas (e.g. the 

 splanchnic area). The modifications of the flow through the area 

 directly, and also through those secondarily, affected, will influence 

 the temperature and chemical changes of the blood, and variations 

 in these will in turn produce their effects everywhere. And so on. 



On the other hand, the turbulence which would be the natural 

 outcome of all these events is softened down, by the compensating 

 effects of which we have spoken, into the smoothness which we call 

 health. Still, the greatness of the possibilities of change which lie 

 hidden in the body are clearly enough shewn by the violence of 

 disease, when compensation fails of accomplishment. 



