348 BOTANICAL GAZETTE [NOVEMBER | 
Pennsylvania chestnut tree blight disease commission indicated 
that the tannin content of the diseased bark was higher than that 
of the healthy bark. This report appears to contradict the idea 
that tannin in the bark is toxic to the fungus, otherwise the fungus 
would be destroyed by the tannin. However, this point was also 
investigated by KERR, who says ‘‘the increment of tannin is only 
apparent and does not really occur. We have found all decayed 
wood and bark give higher tannin contents, no matter what causes 
the decay. It simply means that other constituents have decom- 
posed and disappeared, while the tannin remains practically stable.” 
It is very evident to the writers that commercial tannin is a 
very uncertain substance, as packages of tannin from the same 
manufacturers and supposed to be the same were found to give 
different results when used in cultures. It was also evident that 
ordinary methods of determining tannin are unsatisfactory. There- 
fore, Kerr, a well known technological chemist of Lynchburg, 
Virginia, who has devoted considerable attention to the study of 
tannin, was asked to cooperate in this work. He furnished us with 
three extracts (“1-X,” “2-X,” “3-X,” and ‘“A”’) which are 
described in connection with the experiments. In addition to 
these extracts we also used commercial tannin (MERcK) for com- 
parison. 
Source of cultures 
Cultures of various American species of Endothia, as well as 
foreign strains of some of the species, were obtained from various 
laboratories. In addition, some strains of E. parasitica were iso- 
lated in our own laboratory. We have indicated these by the names 
and the serial numbers used by the laboratories when they came 
to us, except in the case of E. parasitica. In this instance we have 
uniformly referred to this fungus as E. parasitica, without regard 
to whether it was considered a species or a sub-species at the source 
of supply. 
The use of the specific names of E. gyrosa and E. radicalis varies 
in different laboratories, according to SHEAR and STEvENS.S In 
the light of this paper it appears that the fungi from CLINTON 
8 Swear, C. L., and Stevens, F. E., Cultural characters of the chestnut blight 
fungus and its near relatives U.S. Dept. mae Bur. Pl. Ind. Circ. 131. pp. 18. 1913- 
