190 
Walter Stiles and Ingvar Jorgensen. 
the results of the experiments themselves. The experimental plant 
chiefly used was Barley, but supplementary experiments were also 
made with Buckwheat and Balsam. The seeds were soaked in 
water for 24 hours at laboratory temperature (about 20° C), and 
were germinated in moist Sphagnum. The cultures were harvested 
in all cases 50 days after sowing in Sphagnum. Each culture 
occupied a floor space of about 15 cm. x 12 cm. = 180 sq. cm. 
Experimental Results. 
Barley. 
The seed of Barley was of a pure line, and was kindly sent by 
Professor Biffen. The seed was sent in the ear, and in each series 
the seed used was all obtained from a single ear. In this way 
errors due to inherited differences should be reduced to a minimum. 
Ten cultures were aerated, and the same number non-aerated. 
Series 7. 
In the first series Crone’s solution composed as follows was 
used : 
Potassium nitrate ... ... ... 100 gm. 
Magnesium sulphate (cryst.) ... ... 0*25 „ 
Calcium sulphate ... ... ... 0’25 „ 
Ferric phosphate ... ... ... 0*25 „ 
Tap water ... ... ... ... lOOO'OO cc. 
Seeds sown in Sphagnum, May 2. 
Seedlings transferred to culture vessels, May 10. 
Solutions changed, May 23, 30, June 6, 11, 16. 
Cultures harvested, June 21. 
An attempt was made to follow the rate of growth by counting 
the number of leaves at intervals. The results are shown in the 
following table : 
Days after sowing 
Average number of leaves per plant 
Aerated Non-aerated 
8 
2-0 
20 
17 
30 
30 
24 
4-0 
4-0 
29 
5-4 
47 
33 
6 4 
5-6 
35 
7-7 
60 
36 
91 
6-6 
41 
12-0 
8 9 
43 
14 5 
9-6 
45 
15-8 
108 
48 
19-4 
120 
50 
20-3 
12-7 
After 50 days from sowing the aerated cultures thus show 
a markedly greater leaf development, namely an increase of 
