52 MATHEMATICAL BIOPHYSICS OF THE CENTRAL NERVOUS SYSTEM 



In Figure 2 is shown a comparison of equation (4) (curves) with 

 experimental data (points) by H. Woodrow (1914) in which the effect 

 of the interval between warning stimulus and stimulus proper on the 

 reaction-time was measured. The upper curve was obtained under 

 the condition that the successive values of t w in the experiment were 

 mixed randomly; the lower curve was obtained under the condition 

 that the value of t w was kept the same for a number of trials before 

 being changed to another value. As the conditions are different in the 

 two cases, one might expect that the parameters would also be differ- 

 ent. Further details are given in the legend of Figure 2. For a dis- 

 cussion of a mechanism which can differentiate between these two 

 conditions, the reader is referred to Landahl (1939a). 



