224 AGRICULTURAL EXPERIMENT STATION. [Jan. 



they cannot be detected by the unaided eye. These spores 

 remain unchanged during the winter, and are ready for ger- 

 nunation with the seed, when it is planted in the spring. 

 Experiments have shown that the germinating tubes of the 

 smut fungus can penetrate and infect tlie plants of grain only 

 when they are very young seedlings, with very tender and 

 easily penetrable tissues. Having once gained entrance to the 

 mterior of such a plant, however, the fungus grows with the 

 plant, invading the new tissues as they are formed, and 

 finally reaching its complete development by producing its 

 reproductive bodies in the place of the destroyed reproduc- 

 tive bodies of its host. If the grain, with adhering smut 

 spores, be fed to horses or cattle, the spores pass through 

 the body and are voided unharmed. And not merely 

 unharmed ; their passage through the animal body seems to 

 cause them to germinate more readily than before, and 

 they produce, in the manure heap, tiny bodies which 

 increase rapidly by a process of budding similar to that of 

 the yeast fungi. Thus a few spores may produce, in a short 

 time, a multitude of these tiny buds, each of which can infect 

 a grain seedling with the smut parasite. 



Since the infection of neighboring plants cannot be caused 

 by a "smutty" plant, the problem of dealing with the 

 present trouble is much simpler than similar problems con- 

 cerning the numerous fungi which spread rapidly by summer 

 spores. It is evident that it is useless to attempt to save a 

 plant once attacked by smut ; but the facts just stated con- 

 cerning the fungus under discussion point to three lines of 

 defence against its attacks: (1) The conditions for the 

 germination of the seed and the growth of the seedling should 

 be as favorable as possible, in order that the period of 

 susceptibility to infection may be made as short as possible. 

 To this end, well-matured seed should be sown on well- 

 prepared and well-drained soil, in favorable "growing" 

 weather. (2) Suitable commercial fertilizers should replace 

 animal manures, on fields to be sown to grain. This will 

 eliminate from the problem an important comi)lication. (3) 

 The seed grain should be treated, before being sown, with a 

 preparation which will kill the adhering spores, with the 

 least damage to the seed. The best for this purpose seems 



