DESIGN FOR A BRAIN 



3/5 



demonstrate that the method is exact and that it can be extended 

 to any extent without loss of precision. 



The first example is from a physiological experiment. A dog 

 was subjected to a steady loss of blood at the rate of one per cent 

 of its body weight per minute. Recorded are the three variables : 



(x) rate of blood-flow through the inferior vena cava, 

 (y) » „ „ „ » muscles of a leg, 



(2) „ „ „ „ „ gut. 



The changes of the variables with time are shown in Figure 3/5/1. 

 It will be seen that the changes of the variables show a charac- 

 teristic pattern, for the blood-flow through leg and gut falls more 

 than that through the inferior vena cava, and this difference is 

 characteristic of the body's reaction to haemorrhage. The use 



z 



4 8 



Figure 3/5/1 : Effects of haemor- 

 rhage on the rate of blood-flow 

 through : x, the inferior vena cava; 

 y, the muscles of a leg ; and 2, the 

 gut. (From Rein.) 



Figure 3/5/2 : Phase-space and 

 line of behaviour of the data 

 shown in Figure 3/5/1. 



of more than one variable has enabled the pattern of the reaction 

 to be displayed. 



The changes specify a line of behaviour, shown in Figure 3/5/2. 

 Had the line of behaviour pointed in a different direction, the 

 change would have corresponded to a change in the pattern of 

 the body's reaction to haemorrhage. 



The second example uses certain angles measured from a 

 cinematographic record of the activities of a man. His body 

 moved forward but was vertical throughout. The four variables 

 are: 



(w) angle between the right thigh and the vertical 



(x) 



left 



34 



