Indigenous, flourishing, and inured to all the caprices of our climate as the oak is, yet it produces its fruit very precariously, and at times sparingly, like a plant of exotic origin; which does not appear to have been the case formerly, when such herds of swine were maintained by the produce of our woods alone, and grants from manorial lords for permission thus to feed them were recorded with care as valuable obtainments. The cause of infertility in indigenous trees can arise from no defect of construction in the organs of fructification, but from some obstruction, perversion, redundancy, or vitiation of the natural powers; which is particularly manifested by the faculty which they possess at one period of producing fruit, and their impotency at another. This imbecility from one cause or another probably influences at periods every tree or herb that springs from the earth; but in regard to the oak, the most general and probable cause of its sterility is suspended circulation. This is more immediately brought to notice from our custom of barking the timber of this tree in the spring. At times our barkers go on rapidly with their work; yet in a few hours a frost, or a sharp wind, will put an entire stop to their operations, in consequence of the cessation of the flow of sap, which is followed by the adhesion of the bark to the wood. Whenever this nutriment ceases to be supplied, the immature and tender germen must languish; and if the supply be long suspended, it must perish from deficiency of food. That such is the natural effect of spring frosts and sudden chills, more injurious probably to the fruit in this immature state, from its greater delicacy, than when it is more developed, is reasonable to suppose: how far a change of seasons may have taken place to accomplish the injury alluded to, more commonly now than in former periods, we have no criterion for proving; but if failures of the acorn crop took place as frequently in times when swine’s flesh was mostly the diet of the middle and lower classes of people as they do now, the privations of our forefathers were severe indeed.