1917] 



DOUBT— ILLUMINATIXG GAS 



219 



the inverted carboys. By means of the brass stopcocks and glass 

 tubes drawn out to a fine point in the wash bottles, the rate of flow 

 of the gas could be regulated at will. To keep the soil from plug- 



TABLE I 



Plant 



Gas used and amount in parts 



per million (ppm) 



Response 



Very sensitive plants 



Lathyrus odoratus. . 

 Salvia splendens. . . 

 Mimosa pudica .... 



Ricinus communis. . 

 Datura Stramonium 



« a 



Lycopersicum esculentum 



.. 



a 



u 



a 



Coleus sp 



Hibiscus rosa -sinensis .... 



Acalypha tricolor 



Acacia horrida 



Euonymus japonicus 



Citrus decumana 



Zantedeschia ethiopica . . . 



Pelargonium zonale 



Begonia luminosa 



Fuchsia speciosa 



Populus deltoid es 



Ficus elastica 



Croton tiglium 



Tulipa (several vars.) .... 

 Hyacinthus (several vars.) 

 Carica Papaya 



Illuminating gas, 25 

 Illuminating gas, 25 

 Illuminating gas, 50 



Illuminating gas, 50 

 Illuminating gas, 50 



Ethylene, o. 1 



Illuminating gas, 50 

 Ethylene, o. 2 

 Ethylene, o. 1 



Leaflets died and fell off 

 All leaves showed epinasty 

 Some leaflets fell; others 



showed epinasty 

 Epinasty shown by the leaves 

 Epinasty shown by the young- 

 er leaves 

 Close to the limit for the 



response 

 Epinasty 



Epinasty shown by the leaves 

 No response 



Less sensitive plants 



Illuminating gas, 100 

 Illuminating gas, 100 



Illuminating gas, 

 Illuminating gas, 

 Illuminating gas, 

 Illuminating gas, 

 Illuminating gas, 



1000 

 1000 

 1000 

 1000 

 1000 



Illuminating gas, 4000 



Ethylene, 8 



Illuminating 



Illuminating 



Illuminating 



Illuminating 



Illuminating 



Illuminating 



Illuminating 



gas, 

 gas, 

 gas, 

 gas, 

 gas, 

 gas, 

 gas, 



8000 



8000 



8000 



8000 



10,000 



10,000 



10,000 





Slight epinasty shown by the 



younger leaves 

 Epinasty shown by the older 



leaves 

 Epinasty 

 Some leaves fell 

 Some leaves fell 

 Some leaves fell 

 Youngest leaf arched at the 



base of the blade 

 Leaves fell several days after 



treatment 

 Slight epinasty 

 Epinasty 

 Some leaves fell 

 Some leaves fell 

 Slight epinasty 



Flower buds somewhat injured 

 Flower buds somewhat injured 

 Older leaves fell, the younger 



showed epinasty. 



ging the glass tube inserted in the pot, a small vial with a slit along 

 the side of the cork was fitted over the end of the tube inside the 



melted 



flower pot. The pot was then dipped into 



to prevent too much escape of gas through the lower part of the pot. 



