1908] CROCKER AND KNIGHT—CARNATIONS 261 
reserve food had been exhausted. In another experiment he found 
that soil impregnated with gas was very poisonous to plants, for 
seeds put to germinate in it started, but their roots soon died. A 
Dracaena planted in such soil died in ten days. Far less injury was 
shown when a given quantity of gas was in contact with the portions 
of the plant above the ground than when the same quantity came in 
contact with the roots by being passed into the soil. The roots, he 
concludes, are most sensitive to gas injury. He found potted plants 
of Fuchsia and Salvia only moderately sensitive to illuminating gas 
that was allowed to bubble through the soil. 
LACKNER (7) states that camelias, azalias, cacti, and ivy are much 
‘ injured if kept in rooms where illuminating gas is burned; while 
palms, dracaenas (Acuba japonica), and many other plants escape 
uninjured. He asserts that it remains to be determined whether 
it is escaping portions of unburned gas or products of incomplete 
combustion that produce the injury. 
C. WrHMER (8) calls attention to a severe case of gas poisoning 
in Hanover. Thirteen elm trees along a street showed injuries vary- 
ing with the distance they stood from a leak in a gas pipe. In late 
winter a number of them showed brown discoloration of the inner 
bark, and a falling-off of bark in large patches extending up the 
trunk six feet from the ground. No blue discoloration of the roots 
*ppeared as was reported by Kny and other observers. The author 
asserts that the area of the injury was especially great because of the 
hard-packed Street above the leak. 
Motiscu (9) found that illuminating gas is more injurious to the 
‘Sots of plants than chlorin or carbonic acid. Growth in length is 
retarded by ©.005 per cent. of illuminating gas. If uninjured and 
decapitated roots of corn are grown in illuminating gas, the former 
are Temarkably bent and retarded in their growth in length, while 
the latter grow almost straight and are comparatively vigorous. 
Under the influence of the gas the growth in thickness of the roots is 
Mereased, the greatest thickening occurring where the bending 
® Sharpest. Wher a 10-20 per cent.’ mixture of illuminating gas 
“xerts a stimulus from one side, the roots respond negatively. 
NELjuzow (10) notes some very interesting effects of illuminating 
84S upon the etiolated seedlings of peas and other legumes. WIESNER 
