6 BULLETI]^ 1027, U. S. DEPARTMENT OF AGRICULTURE. 



trace of copper could be 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 1892 the United States Department of Agriculture (9) published 

 the following: 



We take the grouud 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 

 e"\ery 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 \\ith 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 2h 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 other 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 (31) milligrams per kilogram in chocolate; from 

 11.2 to 29.2 (44) and from 9 to 40 (31) milligrams per kilogram in cocoa; from 35 to 250 

 milligrams per kilogram in cocoa .shells (31). 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 (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 



