212 Silver- Leaf Disease, III 



concentrated aqueous extract of the deliquescing fruit-bodies of Co- 

 prinus, the idea prompting this treatment being that the mycelium of 

 Stereum purpureum might be digested, as it were, by the extract seeing 

 that the fructifications of Coprinus undergo autodigestion. Miss Baker 

 carried out only one experiment in this connection and there was no 

 "control." To test this matter further, six silvered trees were injected 

 by us with ripe fruit bodies of a species of Coprinus during 1913, holes 

 being bored into the main stems, in which the fungus was inserted and 

 sealed up. In the following year none of the trees had recovered and 

 two were in a dying condition. In 1915 two of the treated trees re- 

 covered, but it is to be noted that this was the year in which a large 

 number of healthy untreated trees likewise regained a healthy appear- 

 ance. 



[d) Treatment ivifh other antiseptics. 



Reference has already been made to the plugging of the stems of 

 silvered trees with ferrous sulphate. Other antiseptic substances, e.g. 

 salicylic acid, have been used on a limited scale in the same way, but 

 without success. 



In view of Ehrlich's work in medical therapy, the efiect of an injec- 

 tion of neo-salvarsan was tried upon two silvered plum trees in the 

 spring of 1914. Holes were bored into these trees towards the base of 

 the stem and -06 gram of this substance dissolved in 5 c.c. distilled 

 water was poured into each, the holes being afterwards sealed with 

 plasticine. Two injections were made in one tree and one in the other. 

 The tree injected once did not recover, but in the one which was given 

 two doses, the upper leaves wilted soon after the unfolding of the buds 

 and the top of the tree died ; this was probably due to the neo-salvarsan 

 being too concentrated. The lower branches of this tree recovered on 

 the other hand, and other healthy shoots subsequently arose. It is 

 likely that the fungus in this tree was killed by the injection of neo- 

 salvarsan, but a considerable part of the tree also was killed in the 

 process. 



Preliminary experiments on the injection of dilute solutions of cer- 

 tain aniline dyes into the branches of a large plum tree having shown 

 a possibility of success by treatment with these substances, further 

 trials of a more careful nature were made. For this purpose, the main 

 roots of the trees to be experimented with were exposed at about the 

 time of the opening of the buds; one, two or three of the roots were 

 then severed and at once connected bv means of tubing with reservoirs 



