2G7 
comparison. At that date the petals of the pear trees were falling 
and the young leaves just expanding. 
One week after the application notes were taken as to the effect. On 
each tree foliage on the sprayed branch was injured, even where 
the mixture was diluted 5 to 1. The injury consisted of small brown 
specks occurring over the leaves and larger brown spots around the 
margins where the liquid had collected in drops. Besides this there 
was a general yellow appearance and arrested growth. The one-sixth 
strength did very nearly as much damage as the full strength. The 
lichens seemed to be harmed but little. The foliaceous forms were dis¬ 
colored somewhat and were injured the most. They were turned 
slightly reddish or purplish. The fruticose forms were not visibly 
changed. As with the foliage, the results from using different strengths 
of the solution varied but little. The full strength was scarcely more 
effective than the one-sixtli dilution. The strong solution turned the 
foliaceous forms a little redder and scorched the leaves a little more, 
the difference being oidy in degree. An examination of the trees in 
July showed no decided further change in the sprayed lichens, and 
altogether the effect of eau celeste was unsatisfactory and indefinite. 
The injury to the foliage would make no difference because the treat¬ 
ment could be made in winter. 
At the time the experiments with eau celeste were carried on, a 
trial was made with chloride of lime, 1 per cent solution, and bichlo¬ 
ride of mercury, one-tenth of 1 per cent solution. Both of these solu¬ 
tions caused the foliage to become of a sickly yellow color, but had 
scarcely any effect on the lichens. They were turned a little yellow in 
a few places where the solution settled in drops, but the majority 
looked all right. 
CHEMICAL ACTION OF BORDEAUX MIXTURE ON LICHENS. 
Bordeaux mixture seems to have some chemical action on the lichen 
substance. When a drop of it falls upon a dry lichen there is at 
first no visible action. In the course of a minute or two the drop, 
which consists of a clear liquid with the blue, flocculent copper com¬ 
pound suspended in it, begins to turn yellowish, and the lichen beneath 
it takes on the same color. That the color of the liquid was real and 
not due to the lichen beneath it was proved by removing a colored drop 
with a small glass tube, in which it still retained its yellow color. The 
drop gradually becomes yellow and in course of ten or fifteen minutes 
will disappear, partly by evaporation and partly by being absorbed 
by the lichen. The result is a greenish yellow spot, with a few blue 
grains of the copper compound on the surface. It may be that 
there is some substance in lichens that acts on the blue precipitate of 
the Bordeaux and dissolves a portion of it, otherwise how could an 
insoluble compound penetrate a lichen thallus and destroy it ? The 
clear liquid separated from the blue precipitate had no such effect, nor 
