1913] HARVEY—LABORATORY AIR 441 
ethylene-air mixture, gave results similar in kind and degree. 
This fact indicates that the ethylene of the illuminating gas is 
responsible for the reaction. Especially does this seem true in 
the light of similar results obtained by KnicHt and CRocKER on 
sweet pea seedlings. The definiteness of the reaction with one 
part ethylene to 10,000,000 of air leads one to believe the plant 
TABLE I 
PLant A EXPOSED TO I PART ETHYLENE TO 1,000,000 AIR} PLANT B EXPOSED TO 
25 PARTS ILLUMINATING GAS TO 1,000,000 AIR (I.E., APPROXIMATELY 
I PART ETHYLENE TO 1,000,000 AIR); PLANT C THE CONTROL 

























: “i Nastic 
: * Nastic Nastic « 
Number ve Prolifera- Starting of} goopin : folding 
Plant tion at | Leaf fall | ab Be, i: f 
of leaf 7 response heat ate sipsael serail ys ha of petiole; of petiole; lamina of 
ra] A ee ee eee Pe ee Wee ee 
ee ee eng eee Corea Kaba ieee 
he C PO ae beg Se ee ee 
"Ghee SEs CR eeniad Sareea Meee ee eet ce | es 
ROS 7s ee ress ee ye eee ran rea 
ed Se i ee eee ioe pepe ES wo ie i 
3 A ees ree Me Sees oe ec Ree roe 
ee eee eee re caiiect  oere  P stg ee 
45° 
C pie Gee ee arctan Reoemacid  Sion) Me ae Be ny 
4 BAe oe x x 
45 45° (?) 
Bae os Lol Re ny ae x pea Gen eee 
30° 60° 
C Ree ae he ea ee 
5 Bea ie ee ee oS x 
45° 
Be eA ee x 
(?) 45 x 
Cc pa) Pe erent (itor ee wane Gange iay Seas 6 erm HNN es 
6 ee Cee Ee oo a es By x, xx 
go 
a ee x x 
(?) goo | XX 
Cc Mh a a 








X X =very strong response. 
