1915] COOK & WILSON—ENDOTHIA PARASITICA 355 
E. parasitica (American) gave growth on 1-1.6 per cent in one 
week, on 2 per cent in two weeks, and on 2.4 per cent in four 
weeks. Pycnospores were produced rather abundantly on 1.6-2.4 
per cent at the end of two months. 
Endothia radicalis (CLiInton’s E. gyrosa no. 7674) gave a good 
growth on 1.6 per cent in one week, and on 2 per cent three days 
later. In two weeks the growth was greater than with any other 
extract used, the maximum on 1 per cent and 1.2 per cent. 
Pycnidia began to appear on 1.2 per cent in about three weeks 
and finally on 1 per cent and 1.6 per cent, the maximum on the 
last percentage. 
It is very evident that extract ‘‘2-X”’ is not so favorable for 
the growth of the fungus as extract ‘‘1-X.’’ Both these results are 
surprising when compared with those obtained with commercial 
tannin. 
Extract ‘“‘3—X” is the coloring matter of the bark. While this 
is estimated as tannin in bark analysis, its real nature is unknown. 
It precipitates gelatin and combines with hide, but does not give 
the same distinct reactions with metallic salts as do other tannins. 
The sample used was between 85 and go per cent pure. As the 
quantity available was very small, it was used only in the proportion 
of r and 2 per cent. Both E. radicalis (E. gyrosa CLINTON no. 
7674) and E. parasitica (STEVENS no. 1158) were grown on these 
media. 
E. parasitica (American) gave a slight growth on 1 per cent 
‘of the extract in one week. This growth increased slowly, but 
finally became abundant. Germination was retarded for about 
10 days on 2 per cent of the extract, and the growth was never so 
good as on 1 per cent. Pycnospores were found on cultures con- 
taining as much as 1 per cent of the extract during the first week, 
but were never found on the medium containing 2 per cent. 
E. radicalis (Cuinton’s E. gyrosa no. 7674) gave a growth very 
similar to that of E. parasitica, but at the end of two months there 
were few pycnospores on the 1 per cent extract. 
This extract was very toxic; the growth was always unhealthy 
and the production of pycnospores greatly checked. These results 
are surprising in that this extract, which is primarily coloring matter 
