2 12 
Smith and Butler. — Relation of 
appear on the leaves of the plants growing in the absence of potassium, and 
a test for starch and translocation was made. Early in the afternoon, the 
day being bright and sunny, leaves were gathered, boiled in water for a few 
minutes, washed in several changes of alcohol until white, transferred to a flat- 
bottomed white porcelain dish, washed with water to remove the alcohol, 
and then floated in Gram’s iodine solution. The leaves from the plants 
growing in the nutritive solution less potassium gave a starch reaction of the 
same intensity as those from the plants growing in the presence of potassium. 
The plants from which the leaves had been taken were transferred to 
a dark chamber for forty-two hours. The remaining leaves were then 
tested for starch, but none was found. The experiments just described 
were several times repeated ; starch was always found present in the leaves I 
and stems, absence of potassium being without effect on the intensity of the 
reaction obtained, and tests on the rate of translocation, the plants being 
kept in the dark for various lengths of time from eighteen to seventy-two 
hours, gave no evidence at all that absence of potassium interfered with 
this function. 
At the end of twenty-one days the plants growing in the absence of 
potassium had ceased growing and were withering. Nevertheless, the 
green portions of the leaves still assimilated and the starch was translocated 
as readily as from the leaves of the plants growing in the full nutritive 
solution. 
Experiment 2. In this experiment Blue stem Wheat was grown to 
maturity in sand culture, 1,400 grm. sand being used per pot with a water 
content of 60 per cent, of saturation, the water required being partly added 
in the form of nutritive solution F, less potassium. The wheat, after wash- 
ing in distilled water for sixteen hours, was planted 1 cm. deep on April 23, 
enough seed being supposedly planted to allow ten plants per pot, but the 
stand desired was not obtained in all cases. Seven days after planting the 
seedlings had come through the sand about 5 cm., and the experiment 
proper was begun. At this time the eight pots that had been planted were 
numbered consecutively and potassium was added as per the following 
schedule : Pot No. 1 received immediately the requisite complement of 
potassium sulphate to make a full nutritive pabulum ; pot No. 2 received 
the requisite complement of potassium three days later ; pot No. 3, six days 
later; pot No. 4, nine days later; pot No. 5, twelve days later; pot No. 6, 
seventeen days. later; pot No. 7, twenty-two days later; while pot No. 8 
never received any potassium. The experiment was discontinued eighty- 
seven days after potassium was added to pot No. 1, or ninety-four days 
from the day the seeds were planted. 
The plants were measured on the day the experiment was begun, and 
periodically thereafter for sixty-three days. The figures obtained are 
indicated in Table XXIII. A consideration of the data presented in the 
