Infection. 3-7 



The clifl'ereut results obtained by Brefeld and Tubeuf in eoiiuexiou witli 

 'Oat smut may be explained from tiis fact that Brefeld used germinating conidia 

 mixed with earth 'in which oats were planted, while Tubeuf used conidia 

 Avhich had not germinated. In the one case the low temperature was applied 

 after the spores had germinated and it was assumed that in the slowly de- 

 veloping seedlings, owing to the cold, the fungus had penetrated to the grow- 

 ing point, and this produced a high percentage of smut. In the other, the 

 pots were placed in a low temperature during the germination of the spores, 

 with the result that the oats germinated, while there were very few spores to 

 infect them. 



Whatever hinders the rapid development of the seedling and extends the 

 period of infection, will favour the access of the germ-tubes of the germinat- 

 ing conidia to the growing point. 



