Harris, A quantitative study of the factors influencing etc. 
5 
is not to be given the same weight as in the case of coefficients 
of moderate vahies. Again, the N used in the calculation of the 
probable errors is the nnmber of seeds weighed, not the number 
of pods involved, many of the pods furnishing two or more seeds. 
Possibly, the number of pods rather than the number of seeds 
weighed should bave been employed. This would give higher 
probable errors. In view of these facts, much stress cannot be 
laid upon the ratio of the constants to their probable errors. De- 
ductions must be drawn rather from the general run of the constants. 
Consider, first, the relationships for the number of ovules per 
pod. Three of the constants are negative and two are positive. 
The highest is only —.123, while the average of thefiveis—.047. 
Thus the influence of the number of ovules upon seed weight is 
very slender indeed. Expressing it in terms of regression as has 
already been done, * 2 ) we find: 
of Plants 
Regression Straight 
Rate of Change 
Line Equation 
in Grams 
L 
W = 16.4645 — .1597 o 
.0040 
LL 
W = 13.0281 + .2060 o 
.0052 
GG 
W = 17.3881 + .0354 o 
.0009 
NH 
W = 11.0961 — .2806 o 
.0070 
ND 
W = 8.5554 — .2853 o 
.0071 
Thus the highest absolute change in seed weight for a Var¬ 
iation of one ovule per pod is .28 units, or 70/10,000th gram! 
The mean value, regarding signs, is but 24/10,OOOth gram. 
When one takes into consideration that the number of ovules 
and the number of seeds per pod are correlated, 2 ) one can hardly 
assert on the basis of the present materials, extensive though they 
may be, whether there is any relationship at all between the 
number of ovules in a pod and the weight of the seeds which it 
matures. 3 ) 
For number of seeds per pod, the results are steadier. In 
all, the sign of the correlation is negative. In 4 of the 5 cases, 
the constant is nominally significant in comparison with its probable 
error. The mean correlation is —.096. 
x ) Harris, J. Arthur, On the Relationship between the Bilateral Asym- 
metry of the Unilocular Fruit and the Weight of the Seed which it Produces. 
(Science. N. S. 36. 1912, p. 414—415.) 
2 ) For actual constants in many series see ”On the Relationship between 
Bilateral Asymmetry and Fertility and Fecundity.” (Arch. f. Entwicklungs- 
mech. d. Organ. Bd. 35. 1912. S. 500 — 522.) 
3 ) Apparently, the numercial smallness of these correlations and their 
diversity in sign cannot he attributed to regression of a higher Order than 
linear. Diagram 1 shows these lines and the empirical means which they 
smooth. Dr. Roxana H. Vivian of Wellesley College has kindly worked out 
the correlation ratios and applied Blakeman’s test for linearity of regression 
in four of the cases, and (bearing in mind the difficulties involved in testing 
for linearity when r is low) there is no clear evidence that a curve of a higher 
Order would be better than a straight line for expressing the change in seed 
weight due to Variation in number of ovules. 
