Feb. 2,1924 
Tissue Fluids in Cotton 
319 
THE CORRELATION BETWEEN THE MEMBERS OF THE SAME DUPLET 
OR TRIPLET 
A casual examination of the fundamental Tables X to XIII and XV to 
XVIII will have shown that there is a material correlation between the 
sap properties of the plants of the same duplet or triplet. This correla¬ 
tion may, in part, be assumed to be due to substratum heterogeneity 
and in part to the differentiation of the individual duplets or triplets 
from the population as a whole by meteorological and time factors. 
Further evidences of the existence of such differentiating factors have 
been furnished by the correlations between the first and second determi¬ 
nations on plants of the same duplet or triplet as set forth in Tables 
XXI and XXII. 
It might be assumed that the coefficients of correlation between the 
physicochemical constants of the plants of the same duplet or triplet 
will furnish some measure of the susceptibility of these physicochemical 
constants (A, k , k/ A, and P H ) to the influence of (a) the relatively perma¬ 
nent differentiation of the substratum and ( b) the transient differentia¬ 
tion, due to variations in water content and atmospheric conditions. 
The closest correlations would be expected for the characters which are 
more susceptible to external influences. This assumption will be valid 
if all of the physicochemical properties have been measured with an 
approximately equal degree of accuracy, so that the errors of measure¬ 
ment will not materially influence the correlation coefficients. 
We have, therefore, prepared a comparison of the correlations between 
the determinations of the same duplet or triplet in the various cultures. 
This comparison is made in Table XXIV. The constants given are the 
differences between the correlation coefficients as indicated in the head¬ 
ings of the columns. Thus A -k indicates the difference between the 
correlation for freezing-point lowering and the correlation for specific 
electrical conductivity between the members of the duplets or triplets 
of the rows indicated. The original correlation coefficients are given in 
the eight fundamental tables X to XIII and XV to XVIII of constants. 
The probable errors of the differences in the correlations between the 
various constants have not been determined, since we are not sure in 
how far the ordinary statistical theory of the probable error of the dif¬ 
ference between two constants is applicable to the present case. 
We have first to consider the correlation between the osmotic concen¬ 
tration of the plants of the same duplet or triplet in comparison with 
the magnitudes of the comparable coefficients for the other physico¬ 
chemical properties. 
The correlation coefficient for osmotic concentration, A, is in every 
instance higher than that for specific electrical conductivity, k, and in 
every instance higher than that for the ratio of specific electrical con¬ 
ductivity to freezing-point lowering, k/A. It is in nearly every case 
higher than that for hydrogen-ion concentration expressed in terms of 
Ph* 
