SPRAYING FRUITs. 385 
The Bordeaux mixture, as elsewhere shown, is made by the addition of 
lime to a solution of copper sulphate. According to recent investigations, 
the reaction is an exceedingly complicated one, the details of which are 
unnecessary here. It has generally been accepted that the mixture as 
sprayed upon the vines consists for the most part of copper hydrate, 
which upon drying becomes an insoluble compound. We have, therefore, 
first of all, the question toconsider whether the hydrate is as likely to 
prove injurious to health as the sulphate in solution. No direct investi- 
gations upon this point have, so far as we know, been made, It has been 
shown,however, that doses of copper four to five times greater can be ad- 
ministered in an insoluble than in a soluble state. The question now 
briefly stated resolves itself into this: May we, without assuming too 
much, use the facts bearing on the harmfulness or harmlessness of copper 
sulphate when considering copper hydrate and copper oxide? We believe 
that this assumption is not only admissible but is erring upon the safe 
side; in other words, that, if an adult can safely absorb 0.5 gram of cop- 
per sulphate a day without injury, he may with much less fear of ill 
effects absorb the same quantity of copper hydrate and copper oxide. In 
fact, as regards the ill effects of the latter, hygienically considered, there 
is a great deal of evidence which will be considered later. 
Accepting, then, the 0.5 gram as the maximum amount of copper in any 
of the forms discussed that may with safety be daily absorbed, let us see 
how these figures compare with the quantity of this metal found in con- 
nection with properly sprayed fruits as well as some other foods and 
drinks. Analyses to determine the amount of copper on sprayed grapes 
have been made in Germany, France, America, and other countries. The 
results of all these show that grapes sprayed intelligently rarely contain 
more than 5 milligrams (0.005 gram) of copper per kilogram, the average 
being from 2% to 3 milligrams per kilogram. In other words, 1,000,000 
pounds of grapes sprayed in the usual way with the Bordeaux mixture 
would contain from 24 to 5 pounds of copper. To reduce the figures still 
further, each 1,000 pounds of fruit would contain 17.5 to 35.0 grains of 
copper. On this basis an adult may eat from 300 to500 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. 
Turning our attention to another phase of the subject, let us consider 
some other articles of food and drink in no way connected with spraying. 
In the first place, it has recently been shown that grapes which have 
never been treated with any fungicide may contain as much as 2 milli- 
grams of copper per kilogram, two parts in a million, or practically the 
Same as the average amount found in connection with sprayed fruit. 
Finding copper, therefore, in connection with fruit is no indication that 
such fruit has been sprayed with the copper compounds. Perhaps, if this 
fact is remembered in the future, it may prevent hasty conclusions and 
consequent annoyance. 
According to numerous analyses, wheat may contain from 4 to 10 milli- 
_ grams of copper per kilogram, the average being 7.2 milligrams per kilo- 
gram. The United States exported to Europe and other foreign countries 
in 1890, 54,387,767 busheis of wheat, weighing approximately 3,263,266,020 
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