EFFECTS ON CHESTNUTS OF SUBSTANCES INJECTED 
49 
Meta-cresol i/iooo G.M. killed the tissues as it passed up and down 
the tree. The midribs and veins of the leaves browned and exuded a smell 
of creosote. Finally they turned black and shriveled, hanging to the 
twigs as though scorched by fire. Along the sides of the path of the solution 
callus formed. The bark peeled from the injected area and exposed the 
wood. Outside this path the tree was unaffected (PI. I, figs. C and D), 
The dilutions of the carbon compounds injected, with the two above 
noted exceptions, did not, apparently, seriously affect the normal growth 
of the trees, though some of them caused blotching of the leaves. 
Extracts 
Canker extract killed the trees. Water extract of healthy bark did not 
affect them. 
Water 
Water injected into trees for three succeeding years apparently in no 
way modified their growth. 
Discoloration of Leaves Due to Injection 
Some of the solutions injected affected the leaves in so marked a manner 
that one could tell from the type of blotching what base had been introduced. 
Lithium produced the most characteristic blotches of all the substances. 
These blotches appeared irrespective, of whether a carbonate, hydroxide, 
chloride, nitrate, or sulphate was introduced. Usually the tip and the 
edge of the leaf between the veins turned a reddish brown color, giving the 
leaf a scalloped appearance (PI. Ill, fig. Sometimes, however, these spots 
appeared in the parenchyma in the middle of the leaf. A dark line separated 
the green from the brown area. The leaf curled upward. As more lithium 
accumulated, the discolored area advanced toward the midrib. The base 
of the leaf was the last to turn brown. 
Sodium carbonate 1/20 G.M. killed the leaf parenchyma in somewhat 
large irregular areas, which sometimes were in the central part of the leaf 
extending across veins and leaving the leaf edges green. The division 
between green and brown areas was sharply defined. Dilute solutions of 
sodium salts did not blotch the leaves. The potassium salts in the dilutions 
used in the injections did not blotch the leaves. 
Ammonium compounds did not brown the leaves, but ammonium 
sulphate 1/200 G. M. and 1/500 G.M. caused a wrinkling or frilling of the 
leaf edges. This frilled area became translucent and later brittle, and the 
network of small veins showed prominently. Occasionally these wrinkled 
areas looked bleached, and were surrounded by a dark green band. 
The colloidal metals did not visibly affect the leaves. 
Concentrated heavy metal solutions produced three varieties of dis- 
colored leaves; one, a browning of the midrib and veins, which gave the 
