THE BACTEKIAL DISEASE OF CORN 211 



Sometimes masses of semi-transparent, rather firm, gel- 

 atinous material are found upon these external corrosions. 



"After midsummer, especially, the disease becomes 

 apparent through discol orations of the portions of the 

 leaves called the sheaths, which closelv invest the stalk. 

 Thjse leaf-sheaths become variously spotted, as observed 

 from the exterior. Sometimes the watery-brown por- 

 tions are mere specks ; sometimes large irregular patches, 

 and of all grades between these extremes. The discol- 

 orations become brown, of a half-rotten appearance. 

 Occasionally there is a little reddish color, more often 

 bordering the brown. If, now, these aifected leaves are 

 stripped from the stalk, it will be found that tlie evi- 

 dence of injury is much more conspicuous on their inner 

 side. The injured patches are larger, have a more 

 watery appearance, and sometimes are more or less 

 smeared with the same gelatinous substance previously 

 mentioned as occurring on the diseased stem below the 

 ground ; but here on the leaf -sheaths it is usually spread 

 in a thinner coating, or layer, instead of in round masses. 

 This infection of the leaf-sheaths evidently comes later 

 in the season than the first noticed form of the disease 

 on the roots. It seems also to be evenly distributed 

 through the field, and to occur upon large as well as 

 small plants. 



"Finally, the ears are, at least occasionally, aifected. 

 Externally, the appearance of the outer husks is like 

 that of the diseased leaf-sheaths. Internally, in tlie 

 worst stage, the whole ear — husks, which should be still 

 green, young cob and kernels, and the mass of "silks" 

 — is reduced to a moist state of corruption, though not 

 ill-scented. The parts lose their normal rigid, or turgid 

 quality, appear as if wilted, and are packed closely 

 together, if not actually adhering by the gummy exuda- 

 tion from the tissues. Very often these ears subse- 

 quently become moldy, penetrated through and through 



