65 



jection there is a period of low resistance, coming on a few days after 

 injection and lasting any^vhere from a few days to several months. 

 In fact no animal seems to get along well during the time the serums 

 are administered. The idea is to give a number that is known to pro- 

 tect, usually from six to ten, and then stop. In a few months the re- 

 sults are apparent. This ferment -when once formed is inheritable. 

 Now let us examine some of the reports of injections and note what is 

 found when applied to the plant. 



I am simply mentioning a few, the reactions of which were rather 

 noticeable, in an effort to show : 



1st — That a chestnut tree will develop protection against blight. 

 2nd— That some, like the chinquapin x chestnut hybrid, will de- 

 velop a sufficient amount to cure tlie infection with a remarkably 

 small amount of serum. 



3rd — That the infection will heal over. 



4th — That in certain cases the American chestnut will develop 

 enough defense after three doses to at least offer a hopeful prospect 

 providing the top of the tree is protected. 



5th — That the three injections in small American chestnut will not 

 protect against direct innoculation. 



No. 100 

 June 26, 1925. Height 10 ft. Blighted badly at the root. Almost 

 circled. Also two limbs badly blighted. First week no general effect 

 was noted. Locally for a few days the old infection seemed more 

 virulent. July 12 cut out part of the old blighted area at the crown. 

 Only about three-fourths of an inch of the cambium remains and it 

 is affected. It looks, however, as though the disease process has 

 stopped and formed a line of demarcation. July 15th definitely 

 visible amount of callus being thrown out at the old injection site. 

 Progress of the disease seems to have been retarded at all in- 

 fective points. 

 July 15th second injection. Progress of disease does not seem to have 

 advanced but the tree is so nearly surrounded at the base that it 

 may not survive. 

 July 27th third injection. If this tree is saved it will be a miracle on 



account of its far advanced stage at the time of vaccination. 

 August Ith. Tree still alive with no evidence of further invasion. 

 Tree is ffettino- much thicker both above and below the crown in- 



