
          249

commonly on the body and large limbs, but occsionally near
the extermities [extremities] of the branches; if on the body they are found
near the root.  The tree attacked with the disease invariably
dies, usually in three, always before the end of four years.

"Such is, I believe, a pretty accurate description of the
'yellows'." p. 9.
[Good!  Darling's [papers] are more valuable than any
others, early or recent, which I have seen. ]

Mr. Darling takes up and discusses five theories of
causation:

1. " 'That the cause depends in a great measure on a
defect in setting out the trees.' "

Objections.--"The disease attacks trees that have never been
transplanted". * * "Besides, if this cause were the real
one, it would have operated years ago, and in all places
where this defective setting out was practiced; but we find
that the disease made its appearance nowhere till within about
thirty years, in this vicinity not till about ten years ago,
in my own orchard and in the gardens of my near neighbors not
till within three years,  * * Why should this defective
setting out produce the disease in 1830, in the same soil,
subsoil, and exposure, where trees thus planted have flourished
in health for ages?"
        