112 
seven to forty days actually intervened between the time of spraying 
and the time when the test inspections were made. 
It will be sufficient to say, without entering into details, that a 
critical examination of 13,000 scales taken from 8 trees showed that 
86 per cent, of them had been killed by a 19 per cent, emulsion ; and 
an examination of 23,000 scales taken from 11 trees which had been 
treated with a 20 per cent, emulsion showed that 91 per cent, of these 
had been killed. Seven trees, two of which had been sprayed Janu- 
ary II and five March 30 with emulsions containing from 19 to 24 
per cent, of kerosene, were examined June 10, 49,000 scales in all 
being counted, with the result to show that in this case, also, 91 
per cent, of those alive when the treatment was applied had been 
killed by the emulsion. The trees covered by these observations 
were soft maples, lindens, and honey-locusts, but as the percentages 
of benefit do not differ materiallv for these different species they 
need not be separately given. The following table summarizes 
these data. 
When sprayed 
Per cent. 
of 
kerosene 
19 
20 
19-24 
Date of 
count- 
ing 
Scales 
counted 
Percent. 
killed 
December 26 to January 5 
January 11 to 13 
January 11 to 13 and March 30 
Feb. 1 
Feb. 1-2 
June 10 
12,703 
23,061 
48,395 
86 
91 
91 
Injury to Trees. 
As one of the results of an examination of trees previously 
sprayed, made by my inspector June 11 to 13, he reported so serious a 
damage to some of the trees as to cast doubt on the safety of the kero- 
sene spray. At Graceland Cemetery, for example, some soft maples 
had received during the winter an experimental treatment with a 25 
per cent, kerosene emulsion, evidently prepared in the usual way, and 
all these trees were in a conspicuously poor condition, with foliage 
thin-, pale, and shriveled, while that of unsprayed trees among them, 
was heavy and dark green. Many of the trees in Lincoln Park on 
which an emulsion containing 19 or 20 per cent, of kerosene had 
been used, presented the appearance of a similar, although less seri- 
ous, injury. A few, indeed, were dead, and dead branches were 
more numerous on others than usual. 
After a study of the report of my own inspector, Mr. E. O. G. 
Kelly, on the condition of these trees last June, and a full and care- 
ful report on the same subject made to Superintendent Warder by 
Mr. R. W. Braucher, in charge of the spraying operation, and an 
examination of comparative photographs, made under Mr. Brauch- 
