46 



Iheless preserved trees thus reversed in position by placing a covering of 

 cow manure, oat chaff, gkie and ashes on the side of the tree unwisely turned 

 toward the south. "The third case, however, arises when a bread knife is 

 used in grafting etc." Perhaps Hesze has in mind here some parasitic in- 

 fection and attempts to explain it. 



Hesze (p. 312) writes "that canker ("Krcbs") really orginates from the 

 grafting of a tree at the time when the moon lies in the sign of the crab or 

 scorpion . . . ." "This disease may be recognized by the fact that here and 

 there the bark throws up little 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." The Editor makes the following 

 addition to this statement, — "So far as canker is concerned, no one 

 can deny that it often arises high up on the trees, and, in fact, in the accumu- 

 lations of dirt which collect between the trunk and the branches at their 

 crotches. On this account, it is most necessary that the crotches always be 

 kept clean and freed from all dirt. Thus the canker often arises from the 

 same rising sap which produces blight and the two diseases often have but 

 one cause." 



The author clearly describes the phenomenon which we now term limb 

 canker and, instead of "ascending sap," we insert, injuries due to frost with a 

 subsequent infection by Nectria ditissima ; his presentation corresponds with 

 our present conception of blight and canker. 



About this time in France, de la Quintinye wrote "T^e parfait jardinier"^ 

 which is still much sought after. In this we find canker briefly 

 mentioned as a kind of gall (signifie une manierc de ga1le ou dc pourriture 

 seiche), formed in the bark and the wood and often found on pears (Poire 

 oe Robine, Petit Muscat, Bergamotte), on trunks as well as branches. The 

 conception of the swellings of the wood indicated by the term "canker" is 

 found further in the writings of later horticultural authors, as, for example, 

 in Fischer-. * 



The boastful Agricola'^ (born 1672) stands independent, that is, 

 on his personal, repeated and practical experience. His actual service is 

 found in his numerous experiments, carried out from 1712-1715, on the vege- 

 tative reproduction of plants (especially by roots). He devotes the fifth 

 chapter to "occurrences and diseases" and expresses himself, for example, 

 as follows : — "Mildew, Rubigo, however, prevails at times, as a pestilence 

 among trees. In spring, when the earth opens and the enclosed vapors be- 



1 I^e parfait jardinier otc. Par feu Mr. de la Quintinve. Parish 1695. Vol. I., 

 p. 31. 



^ R. P. Christophori Fischefi soc. j, Fleissiges Herrenauge etc. Niirnberg- 1719. 5 

 Section I., p. 168. 



3 Georg- Andrea Agrricola. Philosophiae et Medicinae Doctoris und Physici 

 Ordinarii in Regensburg, Versuch einer allgemeinen Verhmehrung aller Baume, 

 Stauden and Blumengewiichse anjetzo auf ein neues libersehen uhw. von C. G. 

 Brausern. Regensburg 1772. The original title read,— "A new and unheard of ex- 

 periment, well founded in nature and in reason, for the universal increase of all 

 trees, bushes and flowering plants," 1716. 



