1881.] the Peach Tree affected with the “ Yellows.” 975 
cured. If they had been left alone nature’s physician would have 
cured them also. Mature does not cure the yellows. A severe 
frost will kill the heart wood of a tree, producing some of the 
characters of this disease, but the exterior—the vital part— 
remaining unharmed, it will soon return to its healthy condition. 
Disinfectants have been recommended. Mr. A. G. Gulley says 
upon this subject:! “But I look with hope in another direction, 
that of preventives by which we can disinfect the trees or enable 
them to resist or throw off the disease. This idea is strengthened 
by the evidence that a fungus may be the cause. We know that 
the low forms of vegetable life are destroyed by various sub- 
stances and cannot exist in their presence. If the disease is of 
that nature, by the introduction of some of those materials we 
shall disinfect the trees, destroy the germs or prevent its growth.” 
We agree with Mr. Gulley in this, but as far as experiments 
have been tried, the right substance has, as yet, not been found, 
and it is a query whether or not the very agent that may be de- 
structive to the fungus may not also, being unnatural in the cir- 
culation of the tree, destroy it also. 
Mr. Taylor? recommends the use of sulphates and alkalies as a 
Wash to be used on the bark and roots of the trees. It must be 
borne in mind, however, that he is inclined to attribute the dis- 
€ase to the agency of a species of Noemaspora, which I think has 
been clearly shown is not the cause, but that the fungus that pro- 
duces the yellows, both fruit and mycelia, is more internal than 
he claims, and would thus necessitate the introduction of the 
acid, alkali or any disinfectant into the circulation, which would 
Produce an abnormal condition of things physiologically, and 
_ injure the tree itself I have no doubt, however, that if enough 
of these reagents were used the fungus would be destroyed. 
Dr. Kedzie’s recommendation! of the use of potash and phos- 
Phoric acid or superphosphate of lime as an experiment, we con- 
Sider as simply a good preventive, and have discussed it under 
that head. | 
From my work and observations, and from, I think, a scientific 
Standpoint, letting theories alone, the only cure that I can recom- 
mend, is, that the fruit grower, when he notices that any tree in 
his orchard has become diseased, root it out carefully and burn 
‘Mich. Pomological Report, 1878, p. 252. 
* Mich, Pomological Report, 1872, p. 596. 
