EFFECTS ON CHESTNUTS OF SUBSTANCES INJECTED 
51 
but of by-products resulting from injuries caused by its presence in the 
lower parts of the tree. These three variations did not appear on every 
injected tree; sometimes there was but one kind, sometimes there were but 
two kind« of discolored leaves. 
Effect on Trunks 
The holes made for the injections usually were filled with grafting wax 
after the removal of the injection tubes. A callus growing from both sides 
of the wound gradually closed it, leaving a small slit hardly noticeable on 
the tree. Sometimes this callus forced the wax from the hole, sometimes 
completely closed it in. It was found on examining felled trees that callus 
might cover the injection wound while an air space extended from the 
point of injection up and down the tree trunk between the outer bark and 
the wood (PI. Ill, fig. B). This hole or tunnel was caused by the failure of 
the new annual ring to grow at that point, the cambium layer having been 
killed by the injected fluid. Such holes, first noticed in trees injected with 
lithium salts, were found to be a somewhat usual result of injection. Trees 
treated with meta-cresol i/iooo G.M., formaldehyde 04 percent, potassium 
bichromate i/iooo G.M., or mercuric chloride i/iooo G.M., showed these 
holes in marked degree in that the bark cracked and peeled away from the 
treated area. The lithium-injected tree, first noticed, had been injected 
in the late fall and the injection wound had been left uncovered. In the 
spring of the following year, this hole was found filled with water below 
the point of injection. It was uncovered by cutting away the bark. ' There 
was no chestnut blight infection found and callus had formed along its 
sides. It extended from a point at the base of the tree about three feet 
below the point of injection to a point somewhat less than three feet above 
the hole. It was thought that some of these holes might be formed beneath 
the bark by the eroding effect of the extraordinary amount of foreign fluid 
passing through a narrow channel rather than by the toxic character of the 
fluid. Trees injected with methylene blue showed this disintegration in a 
less marked form. Primarily, the nature of the solution injected deter- 
mined the formation of these holes and their size, for an examination of the 
injected trees showed that weak acids, water, and extracts did not produce 
such holes. A tree into which para-nitro-phenol i/iooo G.M. had been 
injected, and in which one injection ran for more than five weeks, showed 
short and rather narrow holes. The colloidal metals produced no holes, nor 
was there an abnormal growth of tissue. 
The "killing" solutions produced no stimulation of growth further than 
the callus which cut off the dead tissue from the living. Solutions more 
dilute did not kill the tissue outright, but caused the formation of wound 
tissue in the growing annual ring and bark. 
