642 The Philippine Journal of Science 1922 
concentration of salts from the soil solutes by increased tran- 
spiration. ; 
In order to obtain some sort of collective idea as to the nature 
of the available experimental data on the subject, the results 
of the different experiments are grouped in Table 1. Where 
more than one experiment was reported with each kind of plant, 
only the average is shown. 
TABLE 1.—Data on the effect of different degrees of humidity and sunlight 
on dry weight and ash content of plants. 
Ash, Dry substance. | Fresh substance. 
acacia _—" Dry or absent Dry or a Dry or | Humid or 
open. ber 5 open. ed. open. | shaded. 
g. g. g. g g 9 i 
Hasselbring---___.-- Tobacco, entire |. 18.25 |. 21.08 |.---.----|.-------- ndiia giaghoateeseeeee 
plant. \ 
4% aie an eee Be Sa Gk: Sapesoes.* ees lize se 22 188.42 | 188.14 993 1, 163 | 
Schloesing ---.-.-.-- Tobacco leaves _..| 21.8 18:0 | 87.4 48 | Senne, See eet ST 
P. ct P;-ct 
Kiesselbach_-------- Corn,entireplant.| 7.01; 7.12 | 218.0 | 287.1 |-.-.-----|----------- | 
Thatcher.......-.--.| Wheat grains__-_-- 2.88 9. 92 fan aewees | eeeeass Bi uruoe trowstemanus | 
Sorauer-.......----- Barley, entire |-....----|--------- 0.287) 0.185) 3.8 8.09 | 
: plant. | 
BO at Pea, entire plant_.; 11.7 10.5 0.107; 0.107, 1. 05 1.24 
Tschaplowitz (5) _---| Tropaeolum majus|---------|--------- Ei.) he 8.7 105703 
Woliag se WI caps 11.67} 1246] 0.4 | 0.5 2.0 2.82 | 
3 ee ASDCOrne = own 10.87; 10.56 0.15 0. 22 0. 82 1.24 | 
DO stincs cess Se 7.89 8.11} 0.11 | 0.13 | 0.4 0. 68 | 
ee Siet2s oi. 10.78 | 10.34) 0.88 | 0.51 | 126) 216 | 
As far as the figures in Table 1 are concerned, it can easily 
be seen that differences in humidity and sunlight have no effect 
on the dry weight and ash content of the plant, and, if anything, 
the effect has been to make plants grown under humid or shaded 
conditions richer in dry matter and ash than those grown in 
dry or open atmosphere. 
EXPERIMENTS 
Material used.—The plant used in this experiment is the to- 
bacco plant, Nicotiana tabacum. The seeds were obtained from 
the plant breeding department of the New York State College 
of Agriculture through the kindness of Mr. Casey Fraser, ac- 
cording to whom the seeds came from an inbred plant. 
Germination—The seeds used in Crop I were germinated be- 
tween layers of moist filter paper in an incubation box. This 
method did not prove to be as convenient as was desired since 
it necessitated the early removal of the seedlings from the ger- 
