Abstract

1. Repeated doses of a uniform amount of adrenalin chloride solution produce the same increase in blood pressure only if the resting level of the pressure immediately preceding the injection is the same in each case.

2. When the resting levels differ, the blood pressure responses to uniform doses of adrenalin vary, the magnitude of the disturbance diminishing as the resting level rises. In other words, a much larger dose is required to produce the same effect at a higher level.

3. When the amount of adrenalin administered is increased arithmetically, the resultant blood pressure rises do not follow suit but bear a logarithmic relationship to the stimulus, obeying the Weber-Fechner Law.