THE MONTHLY BULLETIN. 9 



The actual work of investigation began in February, with a series of 

 inoculations made to determine whether the disease was infectious. 

 Various fungi found in connection with gumming, diseased bark, and 

 the gum itself were all used in these inoculations. Some produced a 

 slight gumming in a short time, but were cured of their own accord 

 without any killing of the bark. The infectious nature of the disease 

 was. however, indicated in an inoculation made in a tree in which, 

 after several months, a typical case of lemon gummosis resulted. 



The history of this tree, its inoculation and subsequent decline, are 



'>^ 





Fig. 2. — Same ti-ee as in Fig. 1, photographed Sep- 

 tember 19th, to show the rapid progress of the 

 disease. (Fawcett, Mo. Bull., Cal. Hort. Com.) 



well worth reviewing. The inoculation was made with a small piece 

 of diseased tissue from a badly gummed tree, taken just at the juncture 

 of the live and dead bark, which was inserted in a cut about an inch 

 long, made with a sterile knife on the north side of the trunk. On the 

 south side of the tree a similar cut was made and a piece of tissue from 

 a healthy tree was inserted as a check. Gum appeared in the cut on 

 the north side of the tree in a short time, and the disease began work- 



