Feb. 2,1924 
Tissue Fluids in Cotton 
303 
Egyptian plants growing beside it in the field. The hybrid has an 
osmotic concentration of its leaf-tissue fluids from 3.9 to 4.3 per cent 
lower than that of the Upland parent in the first series and from 6.2 to 8.2 
per cent lower in the second series of determinations. 
COMPARISON ON THE BASIS OK SPECIFIC ELECTRICAL CONDUCTIVITY 
The comparison of the specific electrical conductivities of the tissue 
fluids of the hybrids with their two parent forms is made in Table XVI. 
which is constructed on the same plan as Table XV. 
The results are uniform throughout in showing a lower specific electrical 
conductivity in the hybrid individual than in either the Egyptian or the 
Upland parent. 
The differences between the hybrid and either the self-fertilized or the 
bulk Pima cultures are relatively large, the averages for the hybrid 
ranging from 0.001409 to 0.002700 reciprocal ohm 23 lower than those 
for the Pima controls. These differences are from 4.3 to 17.3 times as 
large as their probable errors. For the whole series (rows 1, 3, 5, and 7), 
the specific electrical conductivity of the hybrid is lower by 0.002016 
reciprocal ohm in the first series and by 0.002690 reciprocal ohm in the 
second series. These differences are 9.9 and 17.3 times as large as their 
respective probable errors. 
Since the Upland cottons are characterized by leaf-tissue fluids of lower 
specific electrical conductivity than those of Egyptian cottons (p. 291), 
the difference between the hybrid and Upland parent is necessarily 
much smaller than that between the hybrid and the Egyptian parent. 
While the differences in all cases indicate a lower electrical conductivity 
in the tissue fluids of the hybrid than in those of its Upland parent, they 
can not in general be considered significant in comparison with their 
probable errors. 
The differences between the hybrid and the Pima parent (Table XVI, 
column 8) are greater 24 in the second series of determinations than in the 
first series. This is in agreement with the results for osmotic concentra¬ 
tion of hybrid and parent forms discussed above. It is also in con¬ 
formity with the results of a comparison of the differentiation of the 
parental types. 
In the comparison between the hybrid and the Upland parent, where 
the differences are necessarily smaller, the differences between the hybrid 
and the parent form are smaller in the second series of determinations. 
COMPARISON ON TllE BASIS OK THE RATIO OF SPECIFIC ELECTRICAL CONDUCTIVITY TO 
FREEZING-POINT DEPRESSION 
The comparisons are made in Table XVII. 
In the first series of determinations the differences between hybrid and 
parent are in part positive and in part negative in sign. They are gen¬ 
erally small, and can not be considered statistically significant in com¬ 
parison with their probable errors. 
23 In the tables these are given in terms of reciprocal ohmsX io 6 . 
24 Note that since the differences between hybrid and parent form have negative signs, the law of signs 
requires that the differences between the differences have the negative sign when the differences are larger 
in the second series. 
