Priestley and Ever shed. — Growth Studies. /. 231 
reached a balanced proportion in reference to the shoot production, and 
during the winter months the shoot production has been small, possibly 
owing to limiting external conditions. 
The final weighings given below seem to indicate that when the roots 
have reached a steady weight the weight bears a rough proportion to the 
original weight of the cuttings. This correlation is not so well marked as 
in Loeb’s experiments on regeneration in Bryophyllum (6 and 7 ), but his data 
were obtained in a much shorter time. In these Tradescantia experiments 
the growth over the period of the experiment was slow, and probably time 
permitted the smaller cuttings to gain in total mass as compared with the 
larger ones. 
Table HI. 
Tradescantia , Series III. 
Number of 
days' growth. 
Tradescantia, 2 
.5 grm. 
Tradescantia , 
5.0 grm. 
Mean weight of Mean weight of 
Mean weight of 
Mean weight of 
wet roots. 
dry roots. 
wet roots. 
dry roots. 
grm. 
grm. 
grm. 
grm. 
50 
0.569 
0.030 
o -753 
0*039 
57 
0.677 
0*035 
0.946 
0-049 
64 
o* 7 i 4 
0-037 
0.851 
0.046 
7 r 
0.647 
0.039 
o *953 
0*055 
78 
o *547 
0.035 
0.874 
0*055 
95 
0-612 
0-036 
o *944 
0.056 
106 
0*655 
0*035 
0.763 
0.054 
148 
0-618 
0-036 
o*777 
0-056 
300 
1 *35 7 
0.079 
1-573 
0.095 
Experiments with Tomato. 
The cuttings, taken from two varieties of tomato, varied much in size, as 
it was found impossible to accumulate a large enough number of cuttings of 
equal mass at the start of the experiment. For this reason the figures in 
the table are given as the ratio of the wet or dry weight of the roots to the 
original weight of the cutting. 
The cuttings were grown singly, in inverted flower-pots which stood in 
dishes of tap-water. There were fifty cuttings of each variety, and five of 
each were collected at intervals. The experiment was started on July 15, 
and indications of roots were visible on most of the cuttings by July 20. In 
the ‘ Sunrise’ series, secondary roots began to appear after eighteen days, but 
in the ‘ Princess of Wales 5 not until after twenty days. 
The yield of roots was not so regular from cuttings of great original 
variability in size, and we have no evidence that root production would show 
any strict proportion to the original mass of the cutting. The probable 
errors are not given in the table, but are so large that these results, if they 
stood alone, would have no value. However, they may be regarded as sup- 
plying some indication (when the curves in Figs. 5 and 6 are examined) of 
the same relationship with regard to the rate of growth, and the production 
of secondary roots, in the case of the tomato as in the case of Tradescantia . 
S 
