62 
TENTH REPORT. 
get, Puccinia 8, Macrosporium 8, Ustilago 4, corn 2, lupine 1, pea 1. With 
these solutions, there is a similar difference, but not nearly so great as with 
the acids or with copper sulfate. Puccinia resists therefore, 8 times as much 
as the pea of KOH. 
In table VI., there is one rather peculiar result. Corn smut survives in 
the solution at full strength, and perhaps, to some extent, in double strength; 
but it cannot survive one-half or one-fourth strength. Macrosporium, is 
not quite so resistant as corn smut but grows readily in one-half strength. 
It, like the smut, does not grow in a solution one or two grades more dilute. 
Glomerella did not grow in any of the solutions tried. At first glance it 
appears as though the table presented a paradox. But this might be ex- 
plained on the ground that, in the strong solutions, crystalline bodies were 
formed, and by this, the toxic action was reduced. When more dilute, the 
crystal bodies were not formed so extensively, hence the toxic action of 
the solution would not be so materially affected. In still more dilute mix- 
tures, the fungi were able simply to withstand the poison when at this dilution. 
Table VII. presents a similar result to that of VI. But the peculiar part 
of it is, that this should be toxic at all. There is no soluble copper in it as 
shown by the test with potass-ferro-cyanide. There should be nothing in 
the liquor but calcium in some compound or other; but calcium is scarcely 
toxic, at even very great concentration to radicles of seed plants, and should 
be much less toxic, reasoning from the experiments described in this paper, 
to fungi. That the liquor is toxic to fungus hyphae is shown especially 
with Glomerella as it is toxic at even 1/16 strength. The liquor is also toxic 
at double strength to Ustilago and Macrosporium. 
This Bordeaux liquor problem needs further investigation, both physio- 
logically and chemically. From the fact that both tables VI. and VII. are 
similar in respect to the paradox just mentioned, it might reasonably be 
inferred that the liquor part, as well as the solid parts play some role in the 
action of Bordeaux mixture as a fungicide. 
Agricultural College, April 4, 1908. 
