110 GENERAL REMARKS 



']'hc blij^lil is evidently milking Siul work in many parts of New-York. Both apple and 

 pear trees are injured by this destroyer. We have in one instance observed from fifteen 

 to twenty recently dead lim!>s upon a single tree. \Vhat is quite remarkable and beyond 

 comprehension, is tlie fact liiat a single tree is sadly aflfected, while tliose around and 

 equally exposed to tlie operation of general causes, remained untouched. 



It seems from these tacts, th.M in the vegetable as in the animal kingdom, death strikes 

 a blow wliere it is the least expected, and in a manner or by an instrumentality which has 

 hitherto eluded our search. We deem it, in liie present state of knowledge, to be entirely 

 unknown, so far as cause is concerned. Tlie fact of the death and the phenomena ac- 

 companying it are plain enough, but by what agency the blow is struck, is enveloped in 

 tiarkness, unless we regard the atmospheric changes as causes. 



A profouiul ignorance of the cause of tlie blight does not stand alone. If the cholera in 

 the human species is still wrapped in as dark a mystery as ever, it is nothing strange that 

 a disease should attack the vegetable whose cause also should hide itself in the profound. 

 We know far less* of vegetable than of the animal structure, and less of the mode by which 

 the imponderables act. It is not strange, therefore, that we often inquire unsuccessfully 

 after causes, and that we are so frequently obliged to stop our inquiries at negative results. 



This is a theme which may be made as prolific in opinion and theories as the potato 

 disease. Its cause is just as inscrutable. So iu regard to remedies; we know of no couree of 

 treatment which can prevent its occurrence, or stay its progress. Observation and experi- 

 ence, however, in some instances, have determined one thing: that it is better to leave the 

 dead branch upon the tree, than to attempt to arrest its progress by a free removal of its 

 branches. Experience proves, too, that no evil is to be apprehended from a poisoned sap by 

 which the disease may be extended. We take great pleasure in alluding to the experience 

 of E. P. Prentice, Esq., whose fine garden and orchard has suffered excessively by the 

 blight. Three years since his gardener, as we are informed, was directed to make a regular 

 business of removing every limb which was attacked, below all appearance of disease. This 

 was persevered in. In 1847, while the disease has been equally severe, the dead limbs have 

 been sufTered to remain, and it is extremely interesting to observe some of the results. So 

 far from proving the death of the individual from what are usually called poisoned branches, 

 there is an unusual vigor in the parts of tlie branches which remain. The efTect is luuch 

 like that which follows from shortening the branches by the knife. The limbs grow rapidly, 

 and the leaves are of deeper green ; and they continue growing to a period in the season 

 when it is unusual for wood to be formed. What, however, is the most remarkable result 

 or phenomenon, is the vigor of tbe end of a limb beyond the apparently dead and dry 



* It should be stated, however, that microscopical observations prove that the structure of vegetables and animals 

 scarcely differ. The organs which compost; the individual are formed upon a uniform basis, the cellular tissue. 



Note. It is also advisable to employ lime freely by spading it in the soil, and giving occasional dressings of the 

 oxide of iron obtained from tlie forges of smiths. I would discard the use of organic manures which favor a rapid 

 growth or swelling out of the cellular system, without imparting sufTicient vigor to resist those causes which are active 

 in developing this disease. These considerations are otTered on physiological grounds, rather than on personal 

 experience. Still I believe they will be found useful, even if not perfect preventives of this mysterious malady. 



