884 MINNESOTA STATE HORTICULTURAL SOCIETY 
(2) Are the salts found in sufficient quantity upon the fruit at the 
time of harvest to prove injurious to health? 
No doubt the majority of people, including physicians, would answer 
the first statement at once by saying that copper is a poison. When we 
come to look carefully into the matter, however, it is found that the very 
best authorities differ on the subject. For more than a hundred years 
the question as to the poisonous nature of copper has been discussed, and 
yet, after reading all the testimony,:it is exceedingly difficult from the 
evidence adduced to form a definite opinion. 
In 1885 the question was discussed before the Belgium Royal Academy 
of Medicine for seven months, the object being to obtain some authorita- 
tive data as to the effect of copper contained in French canned vegetables 
on the public health. While it was finally decided that the copper com- 
pounds in foods were harmful, no direct stand as to the poisonous nature 
of the substances was taken. Those who antagonized the view that cop- 
per was an actual poison cited many eminent authorities to bear out their 
assertions. In the whole discussion, however, it was remarkable that 
not a single case of injury to health, resulting from the daily absorption 
of small quantities of copper, was given. Many instances were cited, 
however, where foods containing copper in considerable amounts were 
daily consumed without any ill effects whatever. It is interesting to note 
in this connection that, notwithstanding the discussion before the Bel- 
gium Academy, the law of July 1882, prohibiting the use of copper in the 
re-greening of fruits, was repealed by the French authorities in the De- 
partment of the Seine. It appears, therefore, from all the evidence on 
the subject that the question under consideration is not settled by any 
means.. For this reason,alleged cases of poisoning with copper should re- 
ceive the most careful investigation. 
We presume no one will deny that copper in large or even moderate 
doses is unwholesome. Looking at the question from this standpoint let 
us consider the second part of our subject, 7. ¢., are the salts found in 
sufficient quantity in connection with properly sprayed fruit at the time 
of harvest to cause injury to health? At this point it may be well to add 
that all our remarks apply to the Bordeaux mixture, which contains 
about twenty times as much copper as the ammoniacal solution, the only ~ 
additional fungicide worthy of consideration on account of its extended 
use. 
According to Gauthier, professor of chemistry of the faculty of medi- 
cine, Paris, an adult can absorb daily for a period of several weeks with- 
out ill effects from 0.2 to 0.5* gram of copper sulphate, or blue vitriol. pe 
Five-tenths of a gram is usually considered the maximum amount that ¥ 
may be absorbed for any length of time without injury to health, ’ 
although cases are on record where as high as 2, 3, and even 4 grams’ <<’, 
have been absorbed for a number of days in succession withoutanyill — 
effects whatever. Some recent French investigations have shown that a °S 
dog can absorb from 15 to 25 grams of copper sulphate without injury. 
Sheep have been fed 43 grams per day for several days in succession with- 
out any noticeable derangement of the system. 
At this point we are confronted witb a somewhat complex chemical 
question which makes it difficult to obtain results strictly comparable. 
*1 gram equals 15.438 grains. 
