Sept. ar, r9x4 Birds and Chestnut Blight 417 
of the perithecia. Other work (4) has shown that ascospores are not 
washed down the trunks of trees by the rains. The birds, therefore, have 
little, if any, opportunity of collecting ascospores, unless they happen to 
be working on a canker at the time when expulsion is taking place. 
That the pycnospores were not obtained directly from spore horns is 
indicated by the fact that these were very rare during the earlier part of 
the period covered by the tests. Furthermore, the number of spores 
carried by a single bird was much smaller than would be expected if indi- 
vidual spore horns had been brushed off, since a medium-sized tendril is 
known to contain millions of pycnospores. We know that pycnospores 
are washed down the trunks of trees in large numbers even by the winter 
and spring rains (4). Work done in this laboratory shows that viable 
pycnospores can be obtained in abundance from the healthy bark below 
lesions. From the facts cited we are led to the conclusion that the pyc- 
nospores carried by the birds are brushed off from either normal or dis- 
eased bark, or from both, in the movements of the birds over these 
surfaces. 
BIRDS AS CARRIERS OF OTHER FUNGI 
Results from cultures show that a few of the birds (Nos. 7, 10, 23, 27, 
and 33) were carrying a greater number of viable spores of the chestnut- 
blight fungus than of all other species of fungi combined. The reverse, 
however, was true of all other birds, most of which were found to be 
carrying fungous sporesin large numbers. (See Table II.) The number 
of species of fungi other than Endothia parasitica represented in the 
cultures varied from 4 to 14 per bird, with anaverage of 7. (See Table I.) 
Those met with most frequently were various species of Penicillium, 
Cladosporium, and Alternaria. Many of the other fungi, which appeared 
in smaller numbers, were not identified, on account of their failure to 
fruit in culture. 
The microscopic examination of the centrifuged sediments revealed 
the fact that more species of fungi were carried than was indicated by 
the cultures. Spores of different species were distinguished by form, 
size, septation, and coloration. For example, the cultures from bird 
No. 7 indicated the presence of only 7 species other than Endothia para- 
sitica, while the sediment skowed at least 12 different kinds of spores. 
Again, bird No. 23 gave 6 species in cultures and at least 19 by micro- 
scopic examination of the sediment. ‘The types of spores found in the 
sediments of these two birds are illustrated by figures 1 and 2. The 
actual number of fungous spores carried was beyond doubt greater in every 
case than is indicated in Table I. The smaller number of species obtained 
from the cultures was due to the fact that the medium used was not 
suitable to the growth of some of the spores, or that they grew so slowly 
that they were overrun by other more rapid-growing forms before they 
had become visible. 
