202 WILDER BROTHERTON, JR., AND H. H. BARTLETT 
Table XI 
Mean Length in Mm. of Epidermal Cells of Epicotyl of Phaseolus multiflorus, based 
upon Data Given in Tables I-X 
Plant Grown in 
Light 
Plant Grown in Darkness 
Section 
All 
Primary 
Cells 
Undi- 
vided 
Primary 
Cells 
Divided 
Primary 
Cells 
Undi- 
vided 
Primary 
and Sec- 
ondary 
Cells 
Second- 
ary Cells 
All 
Primary 
Cells 
Undi- 
vided 
Primary 
Cells 
Divided 
Primary 
Cells 
Undi- 
vided 
Primary 
and Sec- 
ondary 
Cells 
Second- 
ary 
Cells 
I 
2 
3 
4 
5 
6 
7 
8 
9 
lO 
Entire 
internode 
.087 
.090 
.096 
.135 
.169 
•145 
.162 
.155 
.153 
.144 
.087 
.090 
.096 
.115 
.122 
.112 
.124 
•093 
.117 
.097 
(None) 
(None) 
.090 
.163 
.190 
.179 
.178 
.189 
.170 
.163 
.074 
.087 
.092 
.097 
.096 
.094 
.085 
.087 
.086 
.083 
(None) 
(None) 
.058 
.087 
.088 
.088 
.084 
.085 
.083 
.081 
.187 
•273 
.250 
.225 
.267 
.280 
.259 
.291 
.264 
.242 
.175 
.135 
.147 
.146 
.150 
.163 
.199 
.176 
.129 
.148 
.216 
.274 
.258 
.276 
.250 
.292 
.288 
.316 
.283 
.300 
.109 
.114 
.106 
.130 
.117 
.126 
.138 
•153 
•135 
.153 
.102 
.109 
.108 
.100 
.119 
.130 
•135 
.158 
.141 
.163 
.135 
.102 
.189 
.085 
.090 
.258 
.149 
.282 
.126 
.124 
Table XII 
Statistical Constants Based upon Data Given in Tables I-X 
Plant Grown in 
Light 
Plant Grown in Dark 
Constants 
Primary 
Cells 
Undi- 
vided 
Primary 
Cells 
Divided 
Primary 
Cells 
Undi- 
vided 
Primary 
and 
Secon- 
dary 
Cells 
Secon- 
dary 
Cells 
Primary 
Cells 
Undi- 
vided 
Primary 
Cells 
Divided 
Primary 
Cells 
Undi- 
vided 
Primary 
Cells 
and 
Secon- 
dary 
Cells 
Secon- 
dary 
Cells 
M 
.135 
.102 
.189 
.085 
.090 
.258 
.149 
.282 
.128 
.124 
(mm.) 
a 
.053 
•033 
.040 
•033 
.026 
.097 
.025 
.083 
.040 
.043 
(mm.) 
C. V. 
39-2 
32.4 
26.0 
38.8 
28.9 
37-6 
16.9 
29.4 
31.2 
34-7 
vertical series, from node to node, but for the comparison of very 
similar material, such as ours, it probably affords quite as useful a 
measure of the cell number factor. It will be remembered that the 
normal internode chosen for cell measurements came at the extreme 
upper limit of the range of variation, and that the etiolated internode 
corresponded to a much shorter normal one, the two lengths being in 
the ratio 141 to 103. (The value 103 is obtained by dividing the 
actual length of the etiolated internode, 372 mm., by the factor 3.6, 
