THE QUESTION OF THE TOXICITY OF DISTILLED WATER 395 
the last dilution of i : 64. The experiment was then allowed to run 
24 hours longer. Now the total growth was recorded in each beaker. 
At the same time that this series was set up a duplicate one was 
arranged and placed on the table beside the first. At the beginning 
of the experiment 5 seedlings were placed in each beaker. The total 
growth of the roots of these seedlings was recorded at the same time 
as the other set. In the last beaker of the first set were five seedlings 
that had been placed in the distilled water after they had been grow- 
ing for a stated interval in 5 different dilutions of distilled and tap 
water. In the last beaker of the second series were five seedlings 
that had been immediately placed in distilled water. In this way 
one set of seedlings was exposed to the influence of distilled water 
after gradual changes and the other immediately. In another experi- 
ment the method was varied, in one way, by using mixtures containing 
different ratios of tap and distilled water, and in another way by 
arranging the experiment so that 10 seedlings could be put into the 
last beaker of the series. The change was first made daily, in another 
experiment twice a day, and in the final experiment four times a day. 
In one experiment the records of root growth were made at every 
change in every beaker. The results of these experiments show that 
better root growth was obtained in distilled water when changes from 
tap to distilled water were made gradually instead of suddenly. 
In the following table T and D stand respectively for tap and distilled 
water. 
Where Changes are Sudden 
Tap iT+^D 
Dist. 
34-3 36.5 
374 
31.2 
31-5 
27.5 
Where Changes are Gradual 
Total growth in mm 38.3 43.4 
38 
36.4 
36.3 
34-3 
Greater differences might have been obtained had a more sensitive 
indicator been selected. As far as our experience goes lupines are 
not very sensitive to distilled water injury. When exposed to sudden 
changes they react in a moderate way. When in distilled water fre- 
quently changed to rid the medium of the toxic substances or un- 
balanced condition of the organic and inorganic material therein, 
they live until the nutritive substances in the cotyledons have been 
exhausted. Frank's^^ statement that lupine seedlings are poisoned 
