354 BOTANICAL GAZETTE [NOVEMBER 
true of the American strains to a greater extent than of the 
European. 
GROWTH ON KERR’S EXTRACTS 
Extract ‘‘1-X”’ is described by KERR as the water soluble tannin 
of the chestnut bark. It is insoluble in alcohol and in similar 
solvents. This occurs in quantities of 3-5 per cent in the bark. 
The sample used was between 95 and 100 per cent pure. The 
quantity available would not allow as extensive a series of cultures 
as were used for commercial tannin products. Accordingly, the 
percentages used were 1, 1.2, 1.6, 2, and 2.4 percent. The agar 
remained firm in all cases. Inoculations were made with E. para- 
sitica (STEVENS no. 1158), E. radicalis, and E. gyrosa (CLINTON’S 
no. 7674). 
E. parasitica (American) gave an abundant aerial growth dur- 
ing the third week and of pycnospores during the fifth week. The 
great growth of pycnospores was on 2 per cent, which is about the 
normal amount in the bark. This extract is stimulating in normal 
and subnormal amounts. 
E. radicalis (Cuinton’s E. gyrosa no. 7674) gave a growth 
similar to E. parasitica. At the end of the first week the most 
normal growth was on 1.2 per cent and the maximum on 2 per cent. 
Pycnospores appeared in 10 days and were present on all cultures 
at the end of the fifth week. Finally, it may be said that small 
quantities of this extract are stimulating, and that higher percent-. 
ages produce vigorous growth of aerial mycelium and reduced 
number of pycnospores. It is rather surprising that this extract, 
which is so near pure tannin, is not as toxic as the commercial 
tannin. 
Extract “2X” is in all its reactions similar to that designated 
“t-X,” except that it is soluble both in water and in alcohol. Its 
effect on agar is quite different, however, showing a tendency to 
digest proteids as do acids, and so render the medium viscous. A 
series of cultures was prepared containing 1, 1.2, 2, and 2.4 per 
cent of the extract, and inoculated with E. parasitica (STEVENS no. 
1158) and E. radicalis (Curnton’s E. gyrosa no. 7674). The cul- 
tures of the two upper members of the series were quite noticeably 
viscous. 
