THE QUESTION OF THE TOXICITY OF DISTILLED WATER 393 
mentioned below gave the best water in contact with air that the 
writer could get and one that had a conductivity of 1.4 X IC"^. 
About 5 liters of tap water were first shaken up with animal 
charcoal and allowed to stand, with frequent shakings, for several 
hours, and then transferred to the retort for distillation. This length 
of time is hardly necessary vsince the adsorption equilibrium is reached 
in a comparatively short time. The first 500 cc. distilled over was 
discarded and the last 800 cc. was not distilled. The part left, the 
middle portion, was poured into a second retort to which a little 
concentrated H2SO4 was added and distillation started. The first 
300 cc. (about) was discarded and the last 800 cc. not distilled. The 
middle portion proved to be a medium in which lupine seedlings 
grew very well and it was thought, since previous work had shown 
that dilute solutions of H2SO4 stimulated growth, that some sulphates 
might have passed over. Three tests were made for sulphates but 
none were found. It was thought that here was a suitable water, but 
to allay all suspicions it was again distilled in a third retort to which 
was added a little Ba(0H)2. The middle portion from this distillation 
was caught in a 5-liter Jena bottle, thoroughly cleaned and steamed. 
The water was then aerated. The air was drawn from out-of-doors 
through tubes of calcium chloride, sulphuric acid and potassium 
hydroxide solution. This bubbling process was continued for about 
twenty-four hours. In this water, lupine seedlings made good growth 
and showed not the least sign of injury for three weeks providing the 
distilled water was changed at least twice daily. 
In the following experiment the records were kept for a week. 
The experiment was continued, however, and at the end of three weeks 
the seedlings were in good condition but not as far advanced as the 
checks in tap water. There were 10 seedlings in each beaker. At 
the end of the first twenty-four hours the total average growth in 
distilled water was 33.7 mm. On the following day the average 
increase was 4.5 mm. The increase for each following day is 3.6 mm., 
5.3 mm., 4.3 mm., 7.8 mm. and 7.3 mm. The data for tap water 
follow: At the end of 24 hours the total average for 10 seedlings was 
34.6 mm. Increase during successive 24-hour periods: 11.7 mm., 
15.2 mm., 13.5 mm., 9.6 mm., 11.6 mm., 9.1 mm. It may be noted 
here that the growth is a little better in tap than in distilled water, 
but the rate of increase is of the same order. The growth in tap water 
is quite luxuriant. Analysis of the tap water kindly given me by the 
station chemist, Prof. A. J. Patten, is here appended. 
