Plants as Affected by Fungous Parasites. 169 
329. The Bordeaux Mixture, which consists of a com- 
pound of copper sulfate (323) and lime, is now extensively 
used to prevent many fungi of this class. A standard for- 
mula for the Bordeaux mixture is: Dissolve 6 pounds of cop- 
per sulfate in 4 gallons of hot water; in another vessel slack 4 
pounds of fresh quicklime in 4 gallons of (hot or cold) water. 
When both are cool, pour the contents of the two vessels together 
and add enough water to make 45 gallons of the whole. Metal 
vessels, other than those of brass or copper, should not be used. 
a 
Fic. 75. A scab spot magnified. 
(After Trelease). 
Fic. 74. Apple affected with scab. Fic. 76. Section through a scab 
(the dark spots). Fusicladium dendriticum. - spot, highly magnified. The egg- 
(After Scribner). shaped parts on the right are the 
spores. (After Trelease). 
The hot water is recommended only to hasten the dissolv- 
ing of the copper sulfate. Cold water may be used by sus- 
pending the sulfate therein, in a sack of coarse texture, a 
day or two in advance. i 
Prepared by the above formula, the Bordeaux mixture often 
contains more lime than is needed for the chemical action 
that occurs. To avoid this excess of lime, a chemical test 
may be used, as follows: Pour only half of the slacked lime 
n 
