Mar. 25, rors Dissemination of Chestnut-Blight Fungus 499 
An anemameter was erected in the experimental plot, and from the 
successive readings of this instrument the wind velocities were computed. 
Continuous records of temperature were secured by means of a thermo- 
graph located in a standard instrument shelter near the plot, and by use 
of a rain gauge the exact rainfall in inches was determined. As com- 
plete data as possible were also secured relative to the exact duration of. 
all rains. : 
In describing and locating the stations used for exposure plates, meas- 
urements were made to the nearest diseased trees and to the nearest 
lesions, the horizontal distance being recorded. To supplement the de- 
scription, detailed topographic maps were made, showing the location of 
each station (figs. 1 and 2). , ‘ 
The exposed plates were incubated at room temperature, and two rec- 
ords were usually taken. First, at the end of three days after exposure 
all fungous and bacterial colonies visible were marked and counted, and 
those suspected of being Endothia parasitica were especially noted. After 
six or seven days of incubation the final record on each plate was taken. 
This included the total number of fungi, the number of bacterial and yeast 
colonies, and the number of colonies of E. parasitica, if any were present. 
In case of doubt as to the identity of the latter, owing to crowding by 
other colonies, transfers were made to 3 per cent dextrose agar, on which 
medium the growth of this fungus is even more characteristic than on 
chestnut-bark agar. 
The results obtained in the exposure-plate tests are presented in a 
somewhat stummarized form in Tables I and II. 
TABLE I.—Summary of exposure-plate tests at West Chester, Pa., in 1913, giving number 
of fungous colonies caught 
Num- Number of fungous Total 
ber Length of Total _ | coloniesinany plate.| Total | number 
Date of of exposure time ar pie of esl ad 
rr | ee ria sented. “| Maxie | Mini- | colonies. | Endothia 
posed. : mum. mum. parasitica. 
M: oes H. m. Inches. Pe i 5a : 
. 19.. 18 _to I 39 0. 40 
ae Pai 22 3 to Io 2 19% 1/0 24 I 227 ° 
ar..| m9] 5 to 7 r 48%] 0 26 ° 168 ° 
22...| 20] r%4to 74/1 44 No. ag { 35 2 340 ° 
23..) 25| 4 to 8 2 19 ; 28 I 25 ° 
24.. 17| 4%to 6 1 28%]0 47 I 206 ° 
25..| 19] 4 to 6 | 34 |0 75 5 419 ) 
26..| 20| 4 to 7 r 48/0 95 8 574 fo) 
a7.., 28| 4 to 9%) 2 44% | 0175 70 4 400 904 
28.. 18} 4. to ee. I ey ° 2 : Be 
29.. I to 5% |r 30% \ . { 
oe Bs 4 to biz Ir 5734 Ene 146 ° 363 ° 
3I.. 20} 4 to 7 r 48 ° 32 I 261 I 
Sept.1..) 19] 5 to 622/12 44 ° 12 I 122 ° 
Be 3 19 | 4 to 6 I 37 ° 39 3 a ° 
3... 9] § to 64%|1 3734 | 0 Be) I ; 
4. il 5 I 30 ° 48 5 245 
5... 18! 5 to 6 I 31 ° 49 ° 179 I 
