Ernest Warren 
311 
to exhibit no discontinuity in its inheritance. All intermediate conditions seemed 
to occur in the offspring; for example a parent with much spotting crossed with 
a parent with few spots tended to have offspring with a medium amount of spotting. 
It was quite impossible to sort out the parents or offspring into two or more groups 
of "much spotting," "little spotting," "medium spotting," etc. As far as can be 
judged from the material at hand the units of spotting, if such occur, are so small 
that the series is practically a continuous one. 
The only satisfactory way of dealing with such a character which exhibits 
no discontinuity is the statistical method of Galton and Pearson. From the nature 
of the crossings it may not be always possible to deal statistically with the relation- 
ship of both male and female parent to the offspring. For example, if a single plant 
be crossed with the pollen of a dozen different plants, and families raised, there 
will be one female parent only, but 12 different male parents and twelve different 
mid-parents. Such a method of procedure is not free from objection, but it is the 
only course that is possible with the material at present available. In each plant 
the amount of spotting was determined in the bottom six flowers of the main 
axis, that is in the first six flowers which opened. 
Another point to note is that some of the families were raised from seed obtained 
by self-fertilization. Now, the differences, if any, in the strength of inheritance 
in parthenogenesis, self-fertilization and cross-fertilization have not yet been fully 
investigated from an experimental point of view, and accordingly the heredity 
constants have been calculated both with the inclusion and the exclusion of the 
self-fertilized families. 
Ordinary correlation tables have been made, utilizing the six flowers of each 
plant, and Prof. Pearson's constants have been calculated. 
As an example the following table is given : 
Spotting : Mid-Parent mid Offspring {omitting self-fertilized Plants). 
Mid-parent, 
percentage 
of spotting 
54 
06 
189 
144 
105 
yi 
45 
31 
12 
6 
Totals 
S—ll 
34 
36 
36 
2 
lOS 
12—15 
20 
43 
72 
39 
7 
181 
16—19 
3 
53 
55 
47 
42 
•19, 
24 
4 
2 
258 
20—23 
4 
5 
2 
1 
12 
24—27 
9 
27 
39 
18 
13 
7 
113 
28—31 
5 
1 
5 
28 
29 
2 
2 
1 
2 
78 
32—35 
5 
7 
5 
4 
2 
23 
Offspring, 
percentage 
of 
spotting 
i 
1 
"-I 
•o 
7 
•-I 
«o 
•-I 
fo 
1 
Of 
T 
X 
oi 
fo 
773 
