THE EFFECTS OF ILLUMINATING GAS ON 
ROOT SYSTEMS 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 205 
Epwarp M. Harvey AND R. CaTLIN ROSE 
(WITH NINE FIGURES) 
Introduction 
The injurious effects of illuminating gas upon trees and shrubs 
have been testified to by numerous observers. In 1864 GIRARDIN 
(5) reported severe injuries to trees in several cities of Germany 
which he attributed to escaping illuminating gas. Similar observa- 
tions have since been recorded by many writers, among whom are 
VircHow (17), Kny (8), SpPATH and MEVER (14), EULENBERG (4), 
WEHMER (18), SHONNARD (13), and others. 
The shade tree commissions of every city find themselves face 
to face with this serious problem. The trees of our city streets and 
parks are unusually subject to the various tree-injuring agencies, 
the chief of which are insects, fungi, and atmospheric and soil 
impurities. The two latter factors are particularly characteristic 
of the troubles of city trees. The’ problem of gas injuries, 
therefore, is one of considerable economic importance. City 
foresters should know the exact cause of any tree death, not 
only to enable them to provide means for future protection, but 
also in order to determine with whom responsibility rests for the 
present financial losses. They should therefore be able to say 
with certainty whether or not a tree has been killed by gas in 
the soil. At present this is no small undertaking, because there 
are few, if any, reliable symptoms known by which one may differ- 
entiate with certainty gas injuries from those due to several other 
causes. For example, fungi sometimes quickly become prom- 
inent in a tree injured by gas, as purely a secondary effect (see 
Kwy 8 and Stone 1s); but in a case like this the primary injury 
might easily be attributed to the fungi. It is claimed that char- 
acteristic odors often accompany gas poisonings; sometimes in the 
27] [Botanical Gazette, vol. 60 
