DISEASES. 185 



have been coincidences and not the effect of the remedy. 

 There is much false experience in horticulture and agri- 

 culture, as well as in medicine. 



"These views suggest the expediency of extensively 

 applying a solution of the sulphate of iron by means of a 

 green-house syringe or garden engine to the tops and foli- 

 age of trees, laboring under any of the diseases suspected 

 of a cryptogamous origin. It also becomes a query whether 

 the same agent may not be successfully employed at some 

 period to counteract the potato disease, either by water- 

 ing with it the growing plant, or washing tlie tubers in it 

 in autumn, after they are dug. No injury has ever arisen 

 to pear trees by a free use of a saturated solution of cop- 

 peras. 



" In conclusion, I would observe that- the discovery of 

 the cryptogamous origin of the many disorders of the 

 human system is effecting important changes in their 

 treatment. May we not hope that an extension of these 

 discoveries to the vegetable kingdom, may' resuh as 

 favorably in shaping the practice in diseases of fruits and 

 fruit trees ? " 



4th — Wounds, and the attacks of insects, may bo con- 

 sidered more in the light of mechanical injuries by a loss 

 of substance, hence they belong rather to the department 

 of surgery, and can scarcely be considered as disease. 

 The breaking of a branch, or the removal of a portion of 

 the bark, may inflict a serious injury, but it is one which, 

 under ordinary circumstances, will be recovered from, 

 without any impairment of the health of the tree — unless 

 where the wound is so large that the new growth will not 

 soon cover it over, in which case exposure to the moisture 



