496 



A REVIKW OF OPINIONS OX PKAR TREK BLIGHT. 



origin. The Passe Culinar, for iiisslance, 

 when voung, is particularly subject to it. 

 The Seckel, though generally healthy, is 

 sometimes affected by it. We believe, 

 however, that it is more so now, than when 

 CoxE wrote, some thirty years since. That 

 this kind was occasionally subject to it, 

 we should suppose, would have led him to 

 entertain doubts as to the correctness of his 



theory. 



An opinion has been advanced, of late, 

 that the disease "is an epidemic, that it 

 prevails like other epidemics, and will pass 

 off like them ;" and that infection is trans- 

 mitted by the air. This opinion is open to 

 the same objections as that which ascribes 

 it to electricity, or any atmospheric influ- 

 ence. "The leaves and extremities of the 

 branches would always first indicate its 

 presence. The whole system of sap wood, 

 through which the juices circulate, would 

 soon become so contaminated, that in no 

 case would a withered limb, or discolored 

 patches of bark upon the trunk or main 

 branches, mark, at any one time, the limits 

 of the " infection," but would show that it 

 had progressed so far, that it would be use- 

 less to attempt any remedy. The whole 

 tree would be diseased, as for instance, the 

 peach by the yellows, and not parts of it. 

 If a limb is badly injured by frost, disease 

 may be prevented by cutting it off, but we 

 should as soon think cf stopping the small 

 pox by amputation, as the fire blast, if it be 

 an epidemic. If " an epidemic, like the 

 Asiatic cholera," it would equally affect 

 pears of native and those of foreign origin 

 — as well those standing in " close planta- 

 tions" as those a few feet more distant from 

 each other, upon dry as upon wet soil, and 

 would be as likely to prevail or be as de- 

 structive in one locality as another, in Eu- 

 rope as in our own country. If it be an ob- 



jection to the frozen saj) theory, that it at- 

 tacks "old instead of young trees," it is al- 

 so an objection equally applicable to the 

 belief that the " blight is an epidemic.'' 

 The same difficulty would remain to be ac- 

 counted for, if the fact be as stated, but it is 

 not so. " Saplings in our nurseries" are 

 cut down, as well as those " which have for 

 many years borne fine crops of pears.' 

 Perhaps not as frequently, but still to some 

 extent. " I have noticed," says a careful 

 observer, " this disease to attack pear trees 

 in almost every stage of growth. The time, 

 however, that it appears to be most deci- 

 sively destructive, is about the period of 

 their approach to the degree of maturit)', 

 which promises a remuneration for the anx- 

 ious and attentive cultivator." Nor is it 

 true, as has been supposed, that the frozen 

 sap theory asserts " that the disease is con- 

 tracted at the extremities, and is from 

 thence conveyed through the system by the 

 circulation of the fluids," but that the trunk 

 and main branches are first affected, and 

 that the tree may be seriously, if not fatally 

 diseased, when the extremities appear flour- 

 ishing. Nor does the theory suppose that 

 it arises from severe frost merely, but by 

 sudden and frequent alternations of heat 

 and cold, operating upon the fluids while 

 in circulation. Whether the injury is sus- 

 tained in the spring, or in the fall previous 

 to the season during which the disease 

 shows itself, and the manner in which it 

 operates, may be questions of some doubt 

 with those who entertain this belief. 



A correspondent of Maryland, to \.\ie Ame- 

 rican Farmer in 1821, remarks, " In all the 

 various suggestions as to the cause of this 

 disease, I never heard of one that came near 

 the fact, which is more to be wondered at, 

 as the real cause has been so strongly in- 

 dexed by notorious facts. Such, for in. 



