Fig. 3-8. Changes in volume, increasing upwards as ordinates, of 

 the perfused ear of a rabbit, Oryctolagus, with time in 30 sec 

 intervals as abscissae. In the upper tracing increase in volume is 

 due to dilation of the blood capillaries following the first injection 

 of adrenaline. The lower tracing shows the opposite effect of two 

 later injections of the same dose. This is an example of reversal 

 from a dilator response of the capillaries to a constrictor response 

 with repeated doses (from Burn and Robinson, in Welsh, 1955). 



