as to what occurred in receiver No. 2, I have careful 
966 On the Microscopic and General Characters of [December, 
every season. As no facts in support of this theory have ever 
been published to my knowledge, I shall consider it no further. 
The weight of the evidence is in favor of the vegetable origin, 
and, from my observations, I firmly believe that it is due to a 
fungoid growth. Thos. Taylor, of the Department of Agricul- 
ture at Washington, claims that he may have discovered the 
cause of the disease in a species of Ncemaspora. But the same 
form is reported as occurring on other trees that received no 
harm from its presence. Spores of this genus are known to be 
in the air, and may as often light on other trees as on the peach; 
and it has been demonstrated that they will develop upon the oak 
bark as well as on that of the peach, when the conditions are 
favorable. Some may wish to ask: “Is not that upon the oak a 
different species?” This is-a j@st and_ scientific question that 
immediately arises when such a fact is reported in an investigation 
like this; my answer will be apparent soon. First, however, let 
us see how Mr. Taylor proceeds to experiment : 1 On the Ist of 
July last I commenced a series of experiments, by the moist pro- 
cess, with the bark of a peach tree affected with the yellows. 
Into five glass receivers I placed, respectively, a few drops © 
water, just sufficient to form a moist atmosphere in each. Into 
No. 1 I put a piece of bark affected with the yellows; into No. 2 
a piece of bark from a healthy peach tree; into No. 34 handful 
of peach leaves from the unhealthy tree; into No. 4 4 similar 
quantity from the healthy tree ; and into No. 5 portions of bark 
from the healthy and unhealthy trees mentioned. All the spect 
mens were secured from the outward atmosphere. The tempera= — 
ture of the room in which the specimens were kept was fre- 
quently at 90° F. These conditions were highly favorable to the 
development of such fungous germs as mature under excess of heat 
and motsture.” (The italics are mine.) 
_ After due time has elapsed, he finds mycelia and spores - , 
_ Noemaspora on specimens in receivers Nos. 1 and 5, and say$ 
_ that seemingly the healthy bark in No. 5 was not affected by the 
_ contact with the unhealthy bark. We are left entirely in doubt a 
ly followed 
es his experiments in my own work, and am able to report so 
_ Same forms of Noemaspora may be found on the healthy peri 
melt as on the unhealthy, and further, that the same forms | ee 
* Mich. Pomological Report, 1872, p. 593. 
that the 
