94 
For Plat II, treated with ammoniacal copper carbonate solution, 
there was saved $25.92 worth of fruit at a cost of $4.32, leaving a profit 
of $21.GO, or 500 per cent. 
For Plat III, treated with copper carbonate in suspension, the value 
of the fruit saved was $6.48, the cost of treatment $2.25, leaving a profit 
of $4.23, or 188 per cent. 
For Plat IV, treated with Bordeaux mixture and ammoniacal solu¬ 
tion, the value of the fruit saved was $19.44, the expense of treatment 
$3.34, leaving a profit of $16.10, or 482 percent. A further study of 
these figures, together with those already given, brings out a number 
of interesting points, chief of which may be mentioned the following: 
I. That while the amount of fruit saved by the Bordeaux mixture 
was greater than that by the ammoniacal solution the latter prepara¬ 
tion is, after all, the cheapest. In other words, there was more profit 
in using the ammoniacal solution than the Bordeaux mixture. 
II. A mixed treatment consisting of Bordeaux mixture and ammo¬ 
niacal solution is more profitable than a treatment of Bordeaux mixture 
alone, but not as profitable as the ammoniacal solution alone. 
III. There is nothing whatever to be gained by treating with the 
copper carbonate in suspension when the ammonical solution is at hand. 
COPPER ON THE FRUIT AT THE TIME OF HARVEST. 
The question has often been asked whether there is any danger to be 
apprehended from eating grapes which have been sprayed with the 
Bordeaux mixture and other copper solutions. 
To obtain some information in regard to this matter representative 
bunches were taken from Plat I, which was sprayed eight times with 
Bordeaux mixture. 
The last spraying was made on these vines July 30, and between that 
date and August 28, the day of harvest, only a few slight rains had 
fallen. The fruit showed the mixture plainly, more pronouncedly in fact 
than any treated grapes seen in the market. One kilogram of the clus¬ 
ters (24 pounds), including the stems, which appeared to have the 
greater part of the copper, was weighed out, dried, and analyzed.* 
As a result of this analysis 1 kilogram of the fruit yielded .005 grammes 
(.077 grain) of metallic copper. On this basis every pound of grapes 
treated with Bordeaux mixture contained T f|o °f a grain of copper. 
An adult can take from 8 to 12 grains of this salt without fear of serious 
results, and to get this amount from sprayed grapes he would have to 
eat from a ton to a ton and a half of fruit. 
According to M. Fallot t the minimum amount of copper introduced 
into the human system daily through the food is 1 milligram, a trifle les^ 
* The charring of the clusters was performed at the Department, hut the analysis 
was kindly made by Dr. R. C. Kedzie, Mich. Ag. College. 
t Progrds Agricole et Viticole, June Id, 1890. Bull. 11, Sect. Veg. Pathology, p. 100. 
