280 NEBRASKA STATE HORTICULTURAL SOCIETY. 



In another direction the study of the effects of A'arious gases upon 

 plants has been stimulated by the use of fumigation with hydrocyanic 

 acid gas to destroy various insects upon nursery stock and in greenhouses. 

 In still another direction attention has been directed to the effects of 

 gases of various sorts upon plants thru the application of etherization in 

 the forcing of certain bulbs. 



The writer was recently called upon to visit the greenhouses of Mr. 

 Paul B. Floth, of Omaha, to discover, if possible, the cause of the sudden 

 injury or death of a great variety of plants in his establishment. A pre- 

 liminary examination convinced me that the cause was to be found in 

 some leakage from a gas main. The characteristic symptoms were very 

 evident, particularly upon the several varieties of carnations. Prompt 

 search upon the part of the Omaha Gas Company revealed a break in 

 one of their service pipes across the street from the gi-eenhouses affected. 

 (Figure 1.) At the time the surface of the soil was well frozen, forming 

 a sort of a blanket beneath which the gas was free to move laterally in 

 the dirt. The floor of these greenhouses was beneath the street level, as 

 is not uncommon in greenhouse construction, and the gas entered thru 

 the exposed dirt surface forming the south walls of the houses. 



The effects of illuminating gas and particularly of ethylene, one of the 

 most important constitutents of this illuminating gas, upon carnations 

 has been very critically studied by Crocker and Knight 1908, and some of 

 their conclusions should here be stated. They employed the varieties 

 known in the trade as "Boston Market" and "Pink Lawson." They found 

 that an exposure for three days to one part of illuminating gas in 

 40,000 parts of air was sufficient to kill all the young buds and to prevent 

 the opening of flowers in which the petals were already showing. They 

 found that an exposure for twelve hours to one part of illuminating gas 

 in 80,000 parts of air would cause open flowers of the carnation to close. 

 They are of the opinion that the gas acts directly upon the buds of flowers 

 and not thru the root system by absorption in the soil as some have 

 thought. These same authors also studied the effect of ethylene upon 

 carnations with even more startling results. An exposure for three days 

 to one part of ethylene to 1,000,000 parts of air prevented the opening of 

 flowers whose petals were just showing. An exposure for twelve hours 

 to one part of ethylene in 2,000,000 parts of air was sufficient to cause 

 open flowers to close. 



From these results it is evident that carnations might be injured by 

 quantities of illuminating gas not only too small to smell, but perhaps too 

 slight to be detected at all by the best chemical tests. These same authors 

 have as a matter of fact suggested the use of sweet pea seedlings grown 

 in the dark till etiolated as a fine test for the presence of minute quanti- 

 ties of gas in the air. These seedlings show quite definite reactions when 

 exposed to one part of ethylene in 10,000,000 parts of air. 



The "Scarlet Glow" carnation was in bud at the time the gas entered 

 the gi-eenhouse and the calyx closed up over the balance of the flower 



