460 



A REVIEW OV OPINIONS ON PEAR TREE BLIGHT. 



with a share of support and approbation. It 

 has been ascribed to " cleclricity and atmos- 

 pheric influence," " to a stroke of the sun," 

 " to old nge or long duration of varieties," 

 " to a sudden freezing of the bark," and 

 " to an epidemic transmitted Irom place to 

 place by the air." 



We would, briefly as possible, examine 

 these several opinions. 



The article referred to, published in the 

 Nac-England Farmer in lSi29, is written 

 with considerable ability, and as it embra- 

 ces a statement of facts, important in our 

 inquiries, which may seem to warrant the 

 belief of the writer that electricity or atmos- 

 pheric influence is the cause of the disease, 



had the limb cut ofl' far below the blight 

 and saved the tree, as I did the one opposite 

 to me." 



" While the sap of plants is confined 

 within the proper vessels, it possesses the 

 healthy qualities necessary to it ; but if a 

 rupture take? place at the tender extremi- 

 ties of the limbs, or should no rupture oc- 

 cur, but merely a detention or congestion of 

 sap be the consequence of the powerful ra- 

 rification, which the hot moist atmosphere 

 causes, the sap, by coming and remaining 

 more immediately in contact with external 

 gases, will acquire deleterious qualities 

 wholly unfit for the uses of the plant. Na- 

 tive pears are very seldom touched b}' this 



we will give extracts of some length from it. ! malady, because, in our apprehension, the 



" An exotic pear, such as the Fergalouse, 

 the Biurre, the St. Germain, or the D'An- 

 che, grows very luxuriantly in our climate. 

 They have the capacity of attracting a great- 

 er quantity of fluid nutriment than those 

 trees which are indigenous. The fire 



sap vessels are capable of resisting the va- 

 rious changes of our atmosphere. This is 

 not the case, however, with all our fruit 

 trees, even of those which have for centu- 

 ries been acclimated. The quince trees, 

 for instance, are attacked by a species of 



blight occurs more frequently after a sum- I flfg blight, which often injures them very 

 mer shower in July or August, and during j materially, and I have seen the young wood 

 the sunshine. A shower falling on any j or twigs of the apple tree scathed as if by 



plant, whilst the sun shines fiercely, is al- 

 ways more or less injurious." " I have ac- 

 tually seen the end of a limb perish with 

 fire blight before my eyes Avhilst examining 

 it. I once stood under the shade of a fine 

 St. Germain, while I was directing my gar- 

 dener hoAV to amputate the limb of a simi- 

 lar tree, which stood about ten feet from me ; 

 I discovered the blight immediately after 

 one of those hot showers ; and as is my 

 constant practice, I hastened to the tree, 

 that the injured limb might be instantly 

 separated. Whilst I stood under the St. 

 Germain before mentioned, my eye rested 

 on the horizontal branch before me, and to 

 my surprise I saw the leaves change color 



lightning. In truth the electric fluid seems 

 to be the most likely agent to produce a 

 phenomenon of the kind. When the air is 

 charged with electric matter, the acetary 

 fermentation of the vegetable fluids is more 

 active, and they undergo a change at such 

 times. This is a case well known even to 

 the ignorant, who usually attribute it to 

 thunder. Congestion does not always take 

 place at the extremities of all plants. In 

 the cherry and plum trees, it is confined en- 

 tirely to the bark of the trunk or to the 

 thickest part of the principal limbs. Tall 

 trees are more subject to this disease of the 

 bark, than those which have short bodies or 

 trunks. It proves therefore that a highly 

 from a dingy yellow to a dark brown ! I I rarified atmosphere, accompanied by show- 



