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60
All had eaten of the same purchase of apples. Some of these were yet
unconsumed and they were submitted to the Analyst, who reported that
they showed 7 parts per million of arsenic on the skin. The batch from
which these apples were taken was thereupon surrendered by the
greengrocer, and samples were found upon analysis to contain on the
skin no less than 40 parts per million of arsenic, together with 110
parts of lead, corresponding to 8 and 28 parts respectively in the whole
apple. This probably resulted from the trees being sprayed with lead
arsenate, and though an analysis taken from different samples of the
consignment would vary, yet it is obvious that with this particular
brand of apples it was possible that a person might consume one apple,
and in doing so would consume about 1/15 of a grain of lead arsenate.
This is obviously a dangerous amount, as it is quite conceivable a
person might consume 2 or 3 apples, more especially so as these apples
(American Jonathans) were particularly rosy and attractive. The
presence of this poisonous substance is accounted for by the fact that it
is customary in many countries to spray the apple trees to protect them
against the codlin moth and other pests. This practice is not restricted
to North America, and it is frequently practised in this country. It
does not seem that much danger arises from this practice if it is
properly done, and the following is the method advised by our own
Ministry of Agriculture and Fisheries:—
"The trees should be sprayed with lead arsenate just after the
"petals have fallen. It will be found that there is a period
"of from 7-14 days during which the calyx cup, subsequently
"the eye of the apple, is open, while later it closes. The
"object in spraying is to force the arsenate into the calyx cup,
"where it is retained after the calyx closes, with the result
"that any codlin larva which attempts to burrow through the
"'eye' of the apple is poisoned. It is useless, therefore, to
"spray too late, when the calyx cup is closed, for then the
"poison cannot reach the point at which it will be needed, but
"it is also necessary to wait until the blosom has completely
"fallen to avoid poisoning the bees. A nozzle giving a fine
"spray is usually used, and the spray should be directed as
"much as possible on to the young fruitlets. 1 lb. of lead
"arsenate paste should be allowed to every 20-25 gallons of
"water, or the water may be replaced by a similar quantity of
"Bordeaux mixture, if it is desired to control fungus diseases
"as well. The lead arsenate spray, in addition to checking