Feb. 19,19x7 Arsenical Injury through the Bark of Fruit Trees 
285 
some orchards where they are not present to any considerable extent in 
the soil the trees show corroded crowns and an abundance of arsenic in 
the wood. In the same bulletin he also cites (p. 19) an observation that 
is of especial interest in this connection and is as follows: 
Dr. S. M. Bradbury, Horticultural Inspector of Mesa County for eight years, makes 
the following statement, which is used with his permission. “Bands had been used 
in a certain orchard and on adopting the lime, sal soda and arsenic spray these bands 
were left on the trees, some of them for two or three years. Some of these trees died 
and on examining the bands we found that the bark beneath the bands had been en¬ 
tirely eaten up. The lime and arsenic had collected under the bands and destroyed 
the bark.” 
While Headden does not claim that this evidence is proof positive that 
arsenical compounds are responsible for the death of the trees, he is 
evidently thoroughly convinced that such is the case. His line of argu¬ 
ment presents some points of weakness. He does not prove that trees 
that are uninjured, or not obviously injured, may not contain as much 
arsenic as the injured ones. He does not prove that the arsenic was 
taken through the corroded crowns or that, though poisonous if absorbed 
through the feeding roots, it can attack the cork-protected bark. He 
does not prove that arsenic in small quantities is injurious to fruit trees 
nor does he establish the point of concentration above which it becomes 
injurious. He does not establish points of difference between the injury 
in question and that found in other States on trees planted in virgin soil 
to which no arsenic has ever been applied for any purpose and where, 
therefore, arsenic can not be a factor in causing the injury. While some 
vain search for parasitic fungi and bacteria has been made at the Colorado 
station, their absence is very difficult to prove conclusively, as testified 
to by the many unsuccessful early attempts to discover the crowngall 
organism. 
At least two investigators dissent from Headden’s conclusions. Ball, 
of the Utah Experiment Station, would attribute the cause directly to 
alkali and seepage water, and Grossenbacher, formerly of the New York 
Experiment Station, shows some points of similarity to a form of crown- 
rot prevalent in New York and elsewhere which he attributes to winter 
injury. These discussions will be reviewed later in this paper (see p. 
3ih). 
This very suggestive work of Headden’s, while not accepted by all as 
conclusive, has made a strong impression upon many horticulturists, 
entomologists, and plant pathologists over the country and has pointed 
out the necessity for a study of the physiological aspects of the questions. 
It is highly important to determine beyond all dispute whether or not 
trees are injured at the crowns by arsenical spray mixtures and, if so, 
the conditions upon which this injury is dependent. We have, therefore, 
treated numerous branches of various sizes, trunks, crowns, and roots 
with different arsenical compounds, including those used as insecticides, 
to study the injury to bark and wood if any should be produced. 
