18 HISTORY OF PHYTOPATHOLOGY 



the wheat to be the more seriously affected. He also 

 absolves the sun from all responsibility in bringing on the 

 disease. He regards the rust as the most destructive of 

 all cereal crop diseases. He recommends two methods of 

 control: early sowing of the grain so that it will ripen 

 before the rust comes on; and the sticking of laurel 

 branches in the soil throughout the field, so that the rust 

 may go over on these. Columella, another Roman 

 writer, recommends that great piles of chaff be distributed 

 about fields and vineyards and that these be fired when 

 frost threatens, thus preventing frost injury and rust. So 

 important a part did the rust play in Roman agriculture 

 that a special rust-god pair, Rubigus and Rubigo, were 

 evolved and an annual festival to propitiate them was 

 instituted. A Roman legend explains the rust to be a 

 curse sent on farmers as the result of the act of a wicked 

 boy, who burned a fox which he caught robbing his 

 father's hen roost (Eriksson and Henning, 1896 : 9-11). 

 Summary. This ancient era comprises within itself a 

 very distinct unit in human progress. Particularly is this 

 true of all science and learning. For centuries to follow 

 little or nothing was to be added to the sum of scientific 

 knowledge; what had been gained by the observation and 

 studies of the ancient philosophers was to be all but lost 

 in the darkness of the Middle Ages. This is strikingly 

 true of phytopathologic learning. A careful review of 

 such records as are left to us from this era indicates that 

 considerable advances in an understanding of the fun- 

 damental features of phytopathology had been made. 

 (1) Of the nature of disease in plants little of our modern 

 conception is to be discoveredTn the philosophies of this 

 epoch. On the other hand , tfie observations on immunity 



