264 BOTANICAL GAZETTE [October 



effect of illuminating gas upon the flowering carnation. These 

 growers claimed to have had heavy losses from gas that seeped from 

 defective pipes through the ground into the greenhouses. In some 

 cases it is claimed that the losses occurred during cold weather, when 

 little ventilation was possible and when the ground was frozen, so 

 that upward diffusion from the defective pipes was hindered and 

 thereby lateral diffusion fostered. In all these cases it is claimed that 

 the injuries ceased with the repair or removal of the pipes. 



Upon looking up the literature it was found that no accurate 

 determinations were made upon the effects of illuminating gas and 

 its constituents upon flowers, and that in no case have the toxic limits 

 and relative toxicity of the several main constituents been deter- 

 mined. In short, it is not known in any case whether the toxic limit 

 of the gas is determined by the action of one constituent or by the 

 combined action of several. To answer these questions is the pur- 

 pose of the investigation here reported. 



This paper will deal entirely with the buds and flowers of the 

 carnation, describing in detail the effects and toxic limits of illuminat- 

 ing gas and ethylene. A later paper will give in detail similar data 

 for the other main constituents of illuminating gas, as well as describe 

 the effects of illuminating gas and all its main constituents upon the 

 vegetation of the carnation. The work naturally falls into these 

 two divisions, for, as will be shown by experiments described later, 

 the flowers are far more sensitive to illuminating gas than is the 

 vegetation, and the toxic limit of the gas on the flowers seems (from 

 all the evidence of our experiments) to be entirely determined by the 

 ethylene it contains. 



To determine the relative sensitiveness of buds and flowers on the 

 one hand, and the vegetation on the other, as well as the relative 

 sensitiveness of buds and flowers of different ages, one series of 

 experiments was carried on by exposing entire potted plants to an 

 atmosphere containing small proportions of gas. This was done by 

 setting the plants into an air-tight greenhouse within the laboratory 

 greenhouse, and then running desired quantities of gas into the air- 

 tight greenhouse. This sort of experiment has some serious faults. 

 It does not determine whether the flower is affected directly by the 

 gas contained in the air about it, or whether the effect is indirect by 



