30 HISTORY or PHYTOPATHOLOGY 



ing and horticulture. The "practical" writings of this 

 period differed strikingly from those preceding in the 

 greater emphasis placed upon the treatment. Some 

 of these recommendations sound very modern. For 

 example, Riedel,' in his Garten Lexicon, 1751, gives as a 

 remedy for canker, cutting out the diseased places and 

 coating with grafting wax. On the other hand, his sug- 

 gestion that trees be bled by boring a hole or splitting a 

 root to relieve them of superfluous sap sounds ridiculous 

 (Sorauer, 1909 :43). 



An English gardener, Stephen Hales, 1731, refers to the 

 transmission of canker diseases in budding as evidence of 

 the circulation of sap (Sorauer, 1909 :44). Hales also 

 offers an interesting explanation of the cause of hop 

 mildew and records an epiphytotic of this malady in 1731.* 



These studies of the practical horticulturists reached 

 their climax in the discovery by William Forsyth in 

 1791 of a so-called "composition" or tree cement for the 

 treatment of lesions on trees.^ This was widely ad- 



'■ * Riedel, J. Christ. : Kurz abgefasstes Gartenlexikon nebst einem 

 Garten-Calender, pp. 1-420, Nordhausen, 1751. 



^ Hales, Stephen: Statical essays; containing vegetable staticks; 

 or an account of some statical experiments on the sap in vegetables, 

 being an essay toward a natural history of vegetation; of use to those 

 who are curious in the culture and improvement of gardening, etc., 

 1 : 1-XII + 1-376, London, 1731. (Canker transmission, p. 147; hop 

 mildev*, p. 33.) The earliest edition of this appears to have been that 

 of 1727. There were later editions, including a fourth, issued in two 

 volumes in 1769. 



'Forsyth, William: Observations on the diseases, defects, and in- 

 juries in all kinds of fruit and forest trees; with an account of a peculiar 

 method of cure, pp. 1-71, London, 1791. This was translated twice 

 into German, twice into French, once into Italian, and once into Danish. 

 "\ new and improved edition" of the above is to.be found in the fourth 

 edition of "A treatise on the Culture and Management of Fruit Trees," 

 London, 1806, by the same author, pp. 407-484. 



