67 
obtained. The same results were also obtained in the half-hour treatment, 
and not infrequently an occasional spore in the hour treatment. 
Spores treated one-quarter hour in the one-half per cent. solution would 
show slight germination if cultures were made as soon as removed from 
the solution, but if allowed to become dry and then mounted no spores 
germinated. The longer periods of treatment gave no germination whether 
cultures were made at once or after the spores were allowed to be- 
come dry. 
In the treatment of smut spores with formalin it was found that if 
what ordinarily might be called a small quantity of spores were taken 
very variable results were obtained. This seemed to be due to the im- 
perviousness of the spores, when any number were collected together, to 
the formalin. This feature did not appear to enter into the hot water 
treatment, apparently they were not impervious to the hot water. Prob- 
ably this was largely due to the somewhat oily properties of the formalin. 
Another notable feature of the formalin was its action on the spores 
after their removal from the solution, and which in the shorter periods 
of treatment resulted in no germination of the spores, as against fair 
germination in those mounted as soon as removed from the solution. 
The formalin used was that known to the trade as “Formaldehyde. 
Merck,” a supposedly genuine forty per cent. formaldehyde solution. 
Some indirect references have been found in regard to the action of 
formalin on smut spores. In one of these references the author’ found 
that the spores of species of Ustilago and Tilletia were killed after treat- 
ment for two hours in a one-tenth per cent. solution of formalin. In a 
discussion following the presentation of the paper, Kriiger stated that 
spores of Ustilago carbo were not killed by immersion for twenty-four 
hours in a .05 per cent. formalin solution. E 
EB. A. de Schweinitz? says that a formalin solution of 1:10,000 has been 
recommended for destroying the spores of smut. 
The effect of formalin upon germination of the seed was not very well 
marked. <A slight injury was noticeable, but the percentage of germina- 
tion was good. 
1Geuther; Ber. Pharm. Gesell., 5: 325-330, 1895; Abs. in Chem. Centr. BI., 1896; Abs. 
in Jahresb. Agr. Chem., 19: 418; Abs.in Bull. Ind. Agr. Sta.,65: 34; Abs.in Exp. Sta. 
Record, 9: 569. 
* Yearbook Dept. Agr., 259, 1896. 
