218 



PHYSIOLOGICAL KEGULATIONS 



The same data might be used to correlate rates of change of 

 plasma dilution during recovery with the dilutions prevailing. 

 Each dilution has the dimensions of relative volume, so that the 

 correlation obtained is a net equilibration diagram. This would 

 resemble, in another type of water load, the relations described in 

 §59. 



That some measures of blood concentration may be converted 

 by computation into others by means of equations or equivalents is 

 generally recognized. A familiar one is the transformation of re- 

 fractive indices and specific gravities of serum or plasma into pro- 







or 







-5- 



3 



Q _ 



E 

 _o 

 CL 



10- 



■8 



-6 -4 -2 



Total Water Load 



+2 



■^4 



Fig. 122. Increment in plasma dilution, measured as increment in 1/RI (% of 

 initial), in relation to total water load (% of Bo). Two dogs. The points of test 6d are 

 connected; 6 tests in which most water was withdrawn from the diet for 2 or 3 days; 

 then water was suddenly drunk and the blood was sampled repeatedly. Samples taken 

 within one hour of drinking are not included in the correlation ; the correlation coefficient 

 of the remainder is + 0.68. Combining this figure with the data of figure 118, the com- 

 bined correlation coefficient is + 0.87. Data of Adolph and Kingsley. 



tein concentrations of serum or plasma (Neuhausen and Rioch, '23 ; 

 Weech et al., '35). In general the familiar instances of conversion 

 are those in which chemical entities are largely known. It may be 

 recognized just as readily that any one measure of concentration is 

 equivalent to (accompanies) another, providing their coincidence 

 is measured under and limited to prescribed physiological condi- 

 tions. A case is worked out in figure 123 ; once such a correlation 

 and regression are known, it is quite superfluous for most purposes 

 to measure the same plasma in both ways. The regression line 

 there drawn does not pass through the origin. From this it may 



