6 BULLETIN 1027, U. S. DEPARTMENT OF AGRICULTURE. 
trace of copper could he found on grapes which had been properly 
sprayed with copper mixtures. From this it would seem "that even 
under the most careless use of the copper solutions, no injurious 
effects need be feared, and that when properly applied there will not 
be a trace of copper left upon the fruit at harvesting." 
In 1S92 the United States Department of Agriculture (9) published 
the following: 
We take the ground that fruit sprayed with the copper compounds in accordance 
■with the directions of the department is harmless. * * * For five years the 
copper compounds have been used by hundreds and thousands of fruit growers in 
every part of the United States, yet in all that time not a single authenticated case of 
poisoning, so far as we are aware, has been brought to light. * * * Accepting, 
then. 0.5 gram as the maximum amount of copper in any of the forms discussed that 
may with safety be daily absorbed, * * * that grapes sprayed intelligently rarely 
contain more than 5 milligrams (0.005 gram) of copper per kilogram, the average be- 
ing from 2^- to 3 milligrams per kilogram, * * * an adult may eat from 300 to 500 
pounds of sprayed grapes per day without fear of ill effects from the copper. This 
shows how ridiculously absurd are the. statements that fruits properly sprayed with 
the Bordeaux mixture or any o'ther copper compound are poisonous. * * * 
According to numerous analyses, wheat may contain from 4 to 10 milligrams of cop- 
per per kilogram. * * * We do not see how any foreign country can logically 
object to American fruits on the ground that they contain copper without also ob- 
jecting to wheat. 
"Wheat, howeA-er, does not contain anything like as much copper as some other foods 
and drinks. Beef liver and sheep liver, according to reliable and repeated analyses, 
contain, respectively, from 56 to 58 and 35 to 41 milligrams of metallic copper per kilo- 
gram of fresh substance, while in chocolate the enormous amount of 125 milligrams to 
the kilogram has been found. In conclusion, it is o .:>v necessary to call attention to 
one other matter to show how unjust and discriminating it would be to condemn 
American fruits on the ground that they contain copper in unwholesome quantities. 
Analyses of vegetables that have been regreened by the copper process show that they 
may contain from two to sixty times as much of the metal as sprayed grapes. 
In this connection the presence of copper reported in various 
foodstuffs in the following amounts is of interest: 
From 4 to 10 milligrams per kilogram in wheat (43): 56 to 58 milligrams per kilo- 
gram in beef liver (105); about 40 milligrams per kilogram in sheep liver (35) (100); 
from 5.6 to 20.8 (44) and from 5 to 125 1 31 1 milligrams per kilogram in chocolate: from 
11.2 to 29.2 1 44 ) and from 9 to 40 (31) milligrams per kilogram in cocoa: from 35 to 250 
milligrams per kilogram in cocoa shells (31 1. Instances are cited (77) where as much 
as 270 milligrams of copper per kilo was found in French peas that had been sub- 
jected to the regreening process. Tschirch stated 1 127 | that copper is widely distrib- 
uted in plant and animal bodies, always, however, in small amounts: that it enters 
the animal bodies through food and dust; but that the presence of copper in the bodies 
of man and other higher animals is not to be considered as ' 'normal. " He stated 
further that plants absorb only small amounts of copper from the ground: that no 
danger to health need be expected from the consumption of wine from sprayed grapes 
or of potatoes from sprayed fields, and that even the must of coppered grapes may be 
eaten and the skins (containing 0.006 gram of copper per kilo) used as fodder; that 
spraying with copper against fungous diseases might be continued without fear of 
harm; that only very small quantities of the copper compounds entering the mouth 
