THE QUESTION OF THE TOXICITY OF DISTILLED WATER 399 
the growth rate is increased. This can be shown in gradation. If the 
water is changed once a day, the growth rate changes but little in the 
earlier stages of the life of the seedling in the water. If changed 
twice a day, the growth rate is increased. When changed four times 
a day the best results were obtained. Again a large number of seed- 
lings growing in the water suffer less apparently than a few in the same 
amount of water. It seems that the greater amount of salts leached 
out in one case acts in an antitoxic manner and so corrects the water, 
or the roots might actually reabsorb some of the salts. Some such 
explanation might be given for the condition reported by True to the 
effect "that the leaching process seems to have been somewhat less 
active in the cultures containing the larger number of roots than in 
that containing the smaller number of roots." Some such conclusion 
is more reasonable than to assume that roots under the same external 
condition do not lose salts at approximately the same rate. 
In soils where oxidation is hindered we are told that those sub- 
stances inimical to growth are more apt to be found. The very 
nature of water cultures produces this condition of poor oxidation 
and organic matter collects more rapidly than it can be oxidized. A 
renewal of the medium in which the plants are growing eliminates to 
a greater or less extent the toxic substance present therein, and at 
the same time the roots are living in a solution continually aerated. 
When an experiment is set up with these facts in mind lupine seedlings 
will survive in distilled water until injury from lack of nutritive sub- 
Distilled Water Changed 
Distilled Water Not Changed 
Seedling No, 
Growth in Mm. 
Seedling No. 
Growth in Mm. 
I 
44 
I 
25 
2 
34 
2 
31 
3 
42 
3 
31 
4 
38 
4 
34 
5 
32 
5 
35 
6 
43 
6 
37 
7 
41 
7 
29 
8 
37 
8 
32 
9 
39 
9 
36 
10 
46 
10 
37 
Av. Growth in mm. 39.4 
Av.Growth 
in mm. 32.7 
stances sets in. The rate of growth is also greater. Ten seedlings 
were suspended, as described above, in distilled water. The water 
