24 HISTORY OF PHYTOPATHOLOGY 



in which he gives as the three chief causes of the blighting 

 of trees: (1) superfluous sap with inflammation of the 

 sap; (2) resetting a tree in a position different from that 

 in which it originally stood (he preserved trees thus 

 reversed by coating the south side of the body with a 

 mixture of cow manure, oat chaff, glue, and ashes); 

 (3) using a bread knife in grafting a tree. He subscribes 

 to the ancient superstitions to a marked degree as is 

 evidenced by his opinion that cankers on trees result 

 from grafting the tree at the time when the moon hes in 

 the sign of the crab or scorpion. He says, "This disease 

 may be recognized by the fact that here and there the 

 bark throws up Uttle hummocks under which the tissue 

 is dead and black. This spreads further and further, 

 ultimately infecting the whole trunk. Many scattered 

 causes of canker have been brought forward, but the one 

 given above is the most probable of all" (Sorauer Transl., 

 1914:45,46). 



Reference to the common and destructive occurrence 

 of rusts and smuts in cereal crops again appears in writ- 

 ings on agriculture. Especially in England where these 

 diseases were known under the names of blight and mil- 

 dew they were reported as very destructive during this 

 period. It is interesting that the first law, so far as 

 records show, directed toward the control of a plant dis- 

 ease, was enacted during this period. It was in Rouen in 

 France in 1660 that a decree was promulgated directing 

 the grubbing out and destruction of all barberry plants, 

 as they were held to bear some mysterious relation to 

 epiphytotics of wheat rust (Eriksson and Henning, 

 1896 : 12). 



Summary.— The Renaissance period of the pre-modern 



