Page:Treatise on Cultivation of the Potato.djvu/27

 of one hundred and sixty-four bushels be made in the above-mentioned account, and to afford potatoes sufficient to plant the acre of ground again, eight hundred bushels would still remain; and these, if judiciously given to proper animals, would certainly give twelve hundred pounds of animal food."

Further:—

Mr. Knight's first communication to the Royal Society was a paper "Upon the inheritance of decay among fruit trees, and the propagation of debility by grafting," read April 30, 1795; and, in 1797, he published a "Treatise on the Culture of the Apple and Pear, and on the Manufacture of Cyder and Perry." In this work he repeated the same opinions which he advanced in his paper, viz., that vegetable, like animal life, has its fixed periods of duration; and that however the existence of a variety of a fruit-tree may be protracted beyond the natural life of the original seedling plant, by grafting, or by unusually favourable circumstances of soil or situation, still there is a period beyond which the debility incident to old age cannot be stimulated; and to this he attributed the cankered and diseased state of the most of trees of the old varieties of cyder apples in the orchards of Herefordshire.

This hypothesis was so contrary to generally received opinions, that at first it met with considerable opposition; but the increasing decay of the old fruits, even where grafted on the most vigorous stocks, and the superior healthiness of the new varieties produced from seed, has caused Mr. Knight's theory to be now almost universally adopted. To remedy the ill-consequences that would have followed the decay of old fruits, he set about raising new varieties of apples and pears from seed; but instead of following the old method of merely selecting seeds from good kinds, it occurred to him, that by artificially impregnating blossoms with the pollen of a different variety, possessing qualities of a contrary nature, but calculated, if combined with those of the kind operated upon, to produce excellence, and by then raising plants from the seeds so produced, the chances of obtaining valuable varieties would be considerably increased; and though many of the apples at first raised from seed in this manner did not answer his expectations, he eventually succeeded in creating new varieties of many fruits and excellent vegetables, which have long been cultivated