246 BOTANICAL GAZETTE [APRIL 
TABLE II. 
(Plus sign indicates curve toward higher proportion of oxygen.) 
Initial 
Specin | india | Fuca: [Tame | ote [amma] + | — | 
wn Sr : 10 48-120 Sp) 4-4-1; Once 6 I S 
Boge 3, |e | wo | 34 [Set a | | a 
Raphamss | 34 | sqzo | aoe | a4 | Comtinuaus | oo | 5 | 7 
Totals 63 39 13 a 
These seemingly aerotropic curvatures are invalidated, how- 
ever, by those of another experiment, tabulated below, in which 
166 seedlings of Cucurbita Pepo, Raphanus sativus, and Zea Mays, 
placed parallel to gas chambers containing CO,, and a mix- 
ture of CO, and air (as in fig. 7), gave only 37 curves away 
from the source of CO, as opposed to 129 that were either 
turned toward that gas or were neutral. That the majority of 
the curves in the two experiments were in opposite directions 
relative to the position of similar gases indicates that the « curves 
were not aerotropic. 
TABLE Iii. 
(Pl > 1 a t = ty yj 
\ 6 J 5 
Initial | In chambers 
No. of + 4, |Temper- 
Species individ- fics in ature pg den og wena SZ = o | Angle 
uals of water in cm, |%CO,| Zair 
Cucurbita Pepo .. 29 24-48 as” 2-7 100 4 2 23 5-45. 
pg wc sativus. 40 20-30 can 1-6 Too 5 6 29 5-45, 
a Mays...) : 44 g-22 24-31° 1-6 100 - 9 8 27 5-45. 
Zea Mays... : 45 18-23 21-25° 1-7 75 25 17 6 2: ati 
Zea Mays........ 8 5:5 25° 2-5 50 | 50 2 6 | 5-45 
OURS! 42. | bb 37 22 | 107 
In a series of experiments following these, similarly prepared, 
with the root tips not more than 2 to 5™" from each membrane, 
the results could not be interpreted as showing aerotropism, 
since of 135 seedlings of lupine and radish, 46 turned toward the 
supply of oxygen, 39 away, and 50 were neither positive nor 
negative. 
