August 22, 1913] 



SCIENCE 



279 



to be tested was placed in this vessel, and its 

 feet, tail and head and bill scrubbed vigorously 

 with a sterile brush. The bird was then re- 

 moved and the wash water shaken to secure a 

 uniform suspension. By means of a sterile 

 pipette, one cubic centimeter of this wash 

 water was then added to a second flask of sterile 

 water to make 100 c.c. Using another sterile 

 pipette measured quantities (1 c.c. or fraction) 

 were removed from this dilution flask and 

 plated out in Petri dish cultures in 3 per cent, 

 dextrose agar, plus 10. The plates were incu- 

 bated as nearly as possible at 25° C. and the 

 colonies suspected of being the blight fungus 

 were marked at the end of four days and their 

 later development followed. Whenever neces- 

 sary they were transferred to other culture 

 plates to verify the diagnosis. A determina- 

 tion was made of the number of bacterial and 

 yeast colonies, the total number of fungous 

 colonies, the number of colonies of the chestnut 

 blight fungus and the number of species of other 

 fungi represented. The original wash water 

 was retained and centrifuged later for micro- 

 scopic examination. The entire operation was 

 carried out in a culture room with special care 

 to exclude any sources of error. The following 

 is a summary of results obtained up to May 12. 



Name of Bird 



Hairy woodpecker {Dry- 



abates villosus viUosus)., 

 Downy woodpecker(2)r3/- 



abates pubescens medi- 



anus) 



Flicker {Oolaptes auratus 



luteus) 



Nuthatch {Sitta carotin- 



ensis caroliTiensis) 



Golden-crowned kinglet 



( Begulus satrapa sa- 



trapa) 



Sapsucker {Sphyrapicus 



varius varius) 

 Brown creeper ( Certhia 



familuiris americana). 

 Black and white creeper 



( Mniatilta varia ) 

 Junco ( Junco 



hyemalis) 



Total 36 



No. Car- 

 rying Max. No. Spores 

 Spores of Blight 



of Fungus Carried 

 Bliglit by Single Bird 



Fungus 







757,074 







5,655 



6,565 



7,502 



254,019 







10,000 



The analyses show a direct relation between 

 periods of maximum rainfall and the maxi- 

 mum numbers of spores obtained. During the 

 time covered by the analyses there were four 

 periods of heavy rainfall. The highest num- 

 bers of blight spores were invariably obtained 

 from birds shot two to four days after a period 

 of considerable rainfall. The maximum num- 

 bers for the four periods are as follows : 



The number of species of fungi besides 

 Endothia parasitica carried by the birds varied 

 from four to fourteen as determined from the 

 cultures. A microscopic examination of the 

 centrifuged sediments showed, however, a much 

 larger number, which could be detected by 

 form, size and coloration of the spores. The 

 total amount of wash water for each bird was 

 centrifuged in 10 c.c. quantities and the final 

 amount (about 2 c.c.) containing all the sedi- 

 ment was given a thorough microscopic ex- 

 amination. In sediment from birds which had 

 yielded the high number of spores of the 

 blight fungus it was very easy to find the 

 pycnospores, but in those giving the low re- 

 sults the pycnospores were located with more 

 difficulty, but they could always be found. 

 In no cases were any ascospores found in the 

 sediment. During the time covered by our 

 analyses there were only five periods when 

 ascospores were expelled in the field. The first 

 was on March 21 and the last on April 28. 

 The microscopic examinations substantiate 

 the results obtained by the cultures, since the 

 rate of development of the colonies indicated 

 their origin from pycnospores. 



To summarize, our results show that the spores 

 of the blight fungus carried by birds are pycno- 

 spores and not ascospores and that the maxi- 

 mum numbers are being carried during the 

 few days following rain periods. We are also 

 led to the conclusion that the pycnospores car- 

 ried are hrushed off from either the normal or 



