PATHOLOGICAL ANATOMY OF THE INJECTED 

 TRUNKS OF CHESTNUT TREES. 



(Plates XV-XVIII.) 



By CAROLINE RUMBOLD, Ph.D., Dr. CEc. publ. 



{Read March 3, igi6.) 



While working on tree injection in connection with the chestnut- 

 tree Wight, a large number of Paragon chestnut trees (orchard trees) 

 were made the subjects of experimentation by introducing into their 

 trunks different substances in solutions of varying dilution. The 

 method used in making the injections has been described in 

 Phytopathology (i). 



The injections were made to discover the effect of the chemicals 

 on the chestnut trees and in turn on the parasitic fungus Endothia 

 parasitica (Mur.) A. & A., the cause of the chestnut-tree blight. 

 The reason for undertaking these experiments is mentioned, because 

 the processes devised for this investigation not discussed in this 

 paper, have rendered the phase of results here presented, somewhat 

 uneven and unfinished. Further study on this subject is in progress. 



The chemicals used in the injections were about 50 in number: 

 hydrocarbons, metals and alkali metals. So far an examination of 

 the trunks and branches of injected trees shows that their reactions 

 to the different chemicals were alike in kind but varied in intensity. 

 The effect of the chemicals on the leaves of the trees differed, but 

 this will not be discussed at this time. 



The injected solution passed through the vessels of the youngest 

 and the one year old rings of wood. There were exceptions to this 

 rule, which will be explained later. 



The reaction in the trunk and branches of the tree varied with 

 the distance from the point of injection. The affected region ex- 

 tended up and down the trunk in a line whose width usually was 

 but little more than the injection hole. The cells through which the 



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