54 
Colorado Experiment Station 
juice are more suggestive and that the presence of arsenic in leaves 
which have received no application of spray equivalent to 2.19 parts 
of arsenic acid per million of dried leaves and in the fruit equivalent 
to from 0.51 to 2.3 parts of arsenic acid per million of fresh fruit, are 
still more suggestive, if not satisfactorily conclusive, that systemic 
arsenical poisoning is really the cause of the small size, the bleeding 
and the death of some of our fruit trees. 
Before I state the conclusions of this bulletin it is proper that 
I should express my appreciation of the helpful, kindly interest and 
willing assistance rendered me by the, officers and others connected 
with this station and also to officers of other stations and states. 
Throughout Bulletin 131 1 tried to make it as plain as language 
could possibly make it that I fully appreciated the fact that the subject 
matter of the bulletin was of the most serious character and of very 
great importance. I told the public that my colleagues had urged 
me to take up the investigation and used this language: “These 
statements are not made to devolve any responsibility upon these 
professors, but to show that this view has not been hidden from the peo¬ 
ple or my colleagues and the presentation of this bulletin is not a hasty 
resolve or a thing done without a very keen appreciation of its import¬ 
ance not only to the orchardists of Colorado, but to all orchardists.” 
The same is true in regard to this bulletin. 
It is true that the presence of arsenic in apples from California, 
Michigan, New York, Pennsylvania, Ohio, Illinois, and Colorado 
show that fruit grown on sprayed trees contains arsenic and further 
that this is a general fact, but there is no reason at all for alarm for 
either the health or life of persons eating such pears or apples. Two 
of my assistants and I have tried it, one of us eating nearly 
eight pounds of apples by weight, in twelve hours. The apples from 
Illinois, Ohio, and New York were just as rich in arsenic as those 
from California or Colorado. I repeat that so far as the public is 
concerned there is no reason at all for the least concern. At pres¬ 
ent it seems possible that we may use the sulfid of arsenic with 
less danger than accompanies the use of lead arsenate and we will cer¬ 
tainly use very much less arsenic than in the past. It has 
been demonstrated that if everybody will give his orchard one thor¬ 
ough spray at the time now recommended, using one or one and 
one-fourth pounds of pasty lead arsenate to fifty gallons of water, 
four to four and one-half pounds to the 200 gallon tank, we will have 
fairly clean apples. The preceding statement applies only under favor- 
abe conditions. There can be no doubt but that excellent results have 
been and may be obtained from one spray but there are conditions under 
which one spray will not suffice to supress the injury by the codling 
moth even to a reasonable limit. It seems that the first brood may be so 
long in making its appearance that one may find unhatched eggs and 
pupated specimens representing the first brood on the same date. 
