224 BOTANICAL GAZETTE [march 



killed outright; the others drop their leaves or show epinastic 

 growth of the petioles. 



8. Young trees at least are injured by leakage of illuminating 

 gas too slight to be detected by odor. The foliage shows no injury, 

 and one would not be likely to suspect gas poisoning from the 

 appearance of the tree above ground. Judging from my results 

 with trees, their killing by illuminating gas is a very slow process, 

 going on for months or years. It is certain that enough gas to 

 cause an odor in the vicinity of trees would be enough to injure them 

 seriously. 



I am indebted to Dr. William Crocker for suggestions and 

 help during the progress of the work. 



Winona Federated College 

 Winona Lake, Ind. 



7 



Harvey, E. M., Some effect 

 Bot. Gaz. 60:193-214, 191 5. 



8. 



laboratory air. Bot. Gaz. 56:439-442 



1913 



9. Stone, G. E., Effect of escaping illuminating gas on trees. Mass. Exper. 

 Sta. Report pp. 180-185. 1906. 



10. , Effects of illuminating gas on vegetation. Mass. Exper. Sta. 



Report DD. a v-60. ion. 





< 



LITERATURE CITED 



1. Crocker, Wm., and Knight, L. I., Effect of illuminating gas and ethylene 

 upon flowering carnations. Box. Gaz. 46:259-276. 1908. 



2. Crocker, Wm., Knight, L. I., and Rose, R. C, A delicate seedling test. 

 Science N.S. 37:390. 1913. 



3- , A new method of detecting traces of illuminating gas. Science \ 



N.S. 31:636. 1910. 



* 



4« , Effect of various gases and vapors upon the etiolated seedling 



of the sweet pea. Science N.S. 31:635-636. 1910. 

 5- Fitting, Hans, Untersuchungen iiber die vorzeitige Entblatterung von 



Bltiten. Jahrb. Wiss. Bot. 49:187-263. 191 1. 

 6. Harvey, E. M., and Rose, R. C, The effect of illuminating gas on root 



systems. Bot. Gaz. 60:27-44. 191 5. 







