Sept. 21, 1914 
Birds and Chestnut Blight 
407 
imperfect technique, but our experience leads us to believe that such may 
have been the case. Plates heavily seeded with bacteria and various 
fungi give no accurate or reliable results, since the colonies of the chestnut- 
blight fungus are very slow growing and would be overrun before they 
had reached sufficient size to be visible to the naked eye. Pycnospore 
colonies of this fungus at ordinary laboratory temperatures are barely 
large enough to mark at the end of four days and so would be entirely 
overlooked in plates crowded with bacteria and other fungi (3). 
The negative results reported were based upon analyses of the following: 
Downy woodpeckers, 8; creepers (kind not specified), 3; hairy wood¬ 
peckers, 2; flickers, 4; bluejays, 3; total, 20. 
METHOD USED IN experiments 
Nearly all the birds tested by the writers were shot 1 either at Martic 
Forge or at West Chester, Pa., or in the vicinity of these places, in order 
that use could be made of the rainfall and temperature records which 
were kept at these stations. The birds from Martic Forge were shot in 
or near a 300-acre orchard of badly diseased Paragon trees grafted on 
native stock. Those from West Chester were taken in the main from a 
young coppice growth which is practically 100 per cent diseased. 
Most of the birds were shot from diseased trees, and in many cases 
they were working on cankers at the time of shooting or had been seen 
on chestnut-blight lesions a few minutes before they were killed. They 
were immediately placed in sterile paper sacks for transport to the 
laboratory at the University of Pennsylvania. 
In the laboratory the procedure was, first, to sterilize a moist chamber 
in a Lautenschlager sterilizer for 35 minutes at 150° C. A stiff bristle 
brush was also sterilized in boiling water for half an hour or more. 
Before beginning work in the culture room the hands and arms of the 
operator were washed with soap and water and then in mercuric-chlorid 
solution (1 to 1,000). 
When the moist chamber had cooled to room temperature, a flask 
containing 100 c. c. of sterile tap water was emptied into it. The bird to 
be tested was held in one hand and the feet, wing, and tail feathers and 
the head and the bill scrubbed vigorously with the brush, the operation 
being carried out so that only the parts scrubbed were permitted to come 
in contact with the wash water. The moist chamber was then well 
shaken, so as to secure a uniform suspension, and 1 c. c. of the wash 
water was transferred with a sterile pipette to a second flask containing 
99 c. c. of sterile tap water. With a second sterile pipette 1 c. c. or 
fractions were transferred from the second flask, which had also been 
well shaken, to each of a series of Petri dishes. The dilutions used varied 
1 The birds used in this work were shot by Mr. C. E. Taylor, formerly in the employ of the Pennsylvania 
Chestnut Tree Blight Commission, who also centrifuged the wash water for its sediment. 
