858 
Journal of Agricultural Research 
Vol. XXIV, No. lo 
Table I is significant only to the extent of showing that the method 
gives practical yields even after treatment more than rigorous enough 
to insure destruction of adherent spores. Too many extraneous factors 
are involved to allow significant comparison of such points as percentage 
of germination after different treatments or for different varieties. For 
example, the dryness and age of the seed were not in all cases the same, 
the location of the plots did not insure equal pollination, and the season 
of May to September, 1919, when most of the trials were made, terminated 
in six weeks of successive and violent typhoons that beat down and 
destroyed many plants. 
From a large number of such experiments the following routine for 
the treatment of maize seed was formulated. 
METHOD OF TREATING MAIZE SEED TO DESTROY ADHERENT 
SCEEROSPORA SPORES 
(1) Wet the seed with alcohol for one half to one minute; drain, and, 
while the seed surface is still damp— 
(2) Cover with concentrated sulphuric acid, allow to remain 5 to 10 
minutes, stirring from time to time, then drain off the acid. 
(3) Wash for one hour in running water, stirring the seed occasionally 
to insure complete removal of the acid. 
(4) Plant at once, or dry thoroughly and save for future planting. 
After carefully trying all phases of ^ this method of treatment the 
writer is convinced that it meets successfully the requirements of the 
situation earlier outlined in this paper. By it oospores of Sclerospora 
that may be adhering to the maize seed may be destroyed, while at the 
same time the vitality of the seed is but little impaired. If planted at 
once, the percentage of germination is only slightly reduced, and most 
of the resulting plants are normal in growth and seed production. If 
dried and preserved, the percentage of germination declines gradually, 
but even after three months a sufficient number of normal plants will 
result to meet all practical purposes. 
Preliminary experiments indicate that this method of treatment is 
equally effective against spores of the Physoderma disease of maize, 
which in the Orient involves two causal species (j, p. 114; 12, p. 24^- 
247), one of them already introduced and destructive in the southern 
United States (13). Preliminary experiments have shown also that this 
treatment can be used successfully in the case of teosinte {Euchlaena 
luxurious Schrad.), coix {Coix lachryma-johi L.), and some varieties of 
sorghum {Andropogon sorghum [L.] Brot.). 
In its essential feature, i. e., the use of concentrated sulphuric acid, 
this method is by no means nev/. This reagent has been employed by 
several investigators for sterilizing the surface of many different varieties 
of seed. Brigham (j), for example, has used sulphuric acid to free pop¬ 
corn seeds from mold spores customarily adherent to them; and the 
same reagent is used by the Federal Horticultural Board inspectors to 
destroy anthracnose spores on cottonseed. As modified to meet the 
exacting requirements of maize seed suspected of carrying Sclerospora, 
however, the method, it is hoped, will fill a peculiar need, enabling 
experimental quantities of seed of desirable varieties to be imported 
from quarantined regions afflicted with Sclerospora mildews, and insuring 
that, after treatment, the seed may be planted immediately without 
restriction and without danger. 
