Pepe eee 
ON THE TOXIC PROPERTIES OF SOME COPPER 
COMPOUNDS WITH SPECIAL REFERENCE TO BOR- 
DEAUX MIXTURE. 
JuDSON F, CLARK. 
(WITH SEVEN FIGURES) : 
agent in combating the ravages of plant diseases. Its impor- 
tance from an economic standpoint has attracted to its study an 
unusually large number of investigators, and as a result there is 
a very extensive literature on the toxicology of copper com- 
pounds. The object of the present study was to determine ~ 
more exactly the concentration of the various copper compounds — 
required to inhibit germination or to kill the spores of a fairly — 
large and quite representative selection of fungi grown under 4 
favorable conditions; to determine the effect of various media — 
on the toxicology of copper; and to throw light on the toxi- : 
cology of the Bordeaux mixture. I shall not attempt to review — 
the literature of the subject, except to refer very briefly from 
WITHIN recent years copper has come to be the most valued : 
interested will find work before 1896 quite carefully reviewed by 
Fairchild,* Swingle,? and Evans.3 References and reviews OF 
Hollrung’s Jahresbericht* is especially useful in this connec- 
tion. ‘ 
* FAIRCHILD, D. G.: Bordeaux mixture as a fungicide. Bull. no. 6. Div. Vee 
Path. U.S. Dept. Agric. cm ; 
?SWINGLE, WALTER T.: Bordeaux mixture, its chemistry, physical propertie * 
and toxic effects on fungi and ers Bull. no. 9. Div. Veg. Phys. and Path. U: 
Dept. Agric. 1896. 
3EVANS, WALTER H.: Copper sulphate and germination. Bull. no. 10. Di 
Veg. Phys. and Path. U. S. Dept. Agric. 1896. 
‘HOLLRUNG, M.: Jahresbericht iiber die Neuerungen und Leistungen auf oo 
Gebiete des Pflanzenschutzes. Berlin. 1898 and 1899. 
i [JANUARY 
