SEEDS, in their natural climate, do not degenerate, unless culture has improved them ; and then, upon omission of that culture, they return to their first natural state.
As the benefit of changing species of seeds is from difference of tillage, so the benefit of changing individuals of the same species appears to be from those causes, which are, generally themselves the effects of different climates ; such as heat and moisture, which may also vary very much in the same latitude and neighbourhood ; as the same mountain, in the country of the Mogul (related by Mr. Evelyn, from Monsieur Bernier), on the south side, produces Indian plants, and on the north side European plants, from different exposures ; and some land retaining water longer, is colder ; some suffering it to pass down quicker, and by the nature and figure of its parts causes such a refraction and reflection of the sun's rays, which give a great warmth, as in sand and gravelly grounds that are well situate, and have an under-stratum of some sort of hollow matter, next under the staple, or upper-stratum, wherein the plough is exercised.
  This hollow matter lets the water pass down the sooner from the surface, whereby the staple of the ground becomes the drier, and consequently warmer.
  This beneficial change of individuals seems rather to be from the forementioned causes than from change of food : and these causes show their efficacy, chiefly in the generation, or foetation of those seeds ; as flax-seed brought from Holland, and sown here, will bring as fine flax as there ; but the very next generation of it coarser, and

so, degenerating gradually, after two or three descents becomes no better than the common ordinary sort ; yet its food is the same, when the flax is fine, as when it is course.
  And so it is when individuals of wheat are changed ; so silk-worms, hatched and bred in France, of eggs or seed, brought from Italy, will make as fine silk as the Italian ; but the eggs of these lain in France ; and their issue will make no better silk than the French ; though their food be from leaves of the same mulberry-trees, when they make fine silk and coarse ; therefore it is from the climate where the eggs are impregnated, not where they have their incubation or food when hatched and fed to their lives's end, that this difference happens.
  Common barley sown once in the burning sand, at Patney in Wiltshire, will, for many years after, if sown on different warm ground, be ripe two or three weeks sooner than any other, which has never been impregnate at Patney : but if sown a degree further north, on cold, clayey land, will, in two or three years, lose this quality, and become as late ripe as any other.
  Barley is far from being improved by becoming rath-ripe ; for it loses more good qualities than it gets by being sown at Patney ; it is so tender that if it be sown early the frost is apt to kill it ; or if it be sown late in May on the same day, and in the same soil with the same sort of barley that is not rath-ripe, it will be much thinner bodies than the late ripe ; and besides, if it happens to have any check by cold or drought, it never recovers it as the other doth, at what time soever it is sown. It is now, as I am informed, gone out of fashion, and very few farmers have sown it of late years. I know a little parish that I believe formerly lost about 200/. per ann. by sowing rath-ripe barley ; but long and dear experience hath now convinced them of their error, and obliged them totally to disuse it.

  Indeed, Patney is far from improving the species of barley, except we think it improved by becoming more weak and tender, and shorter lived ; which last-mentioned quality fits it for such countries, where the summers are too short for other barley to ripen.
  The grains, or seeds of vegetables, are their eggs, and the individual plants immediately proceeding from them, have not only the virtues they received in embryo (or rather inplantulis), but the diseases also ; for when smutty wheat is sown, unless the year prove very favourable, the crop will be smutty ; which is an evident token of mala stamina.
  The smutty grains will not grow, for they turn to a black powder ; but when some of these are in a crop, then, to be sure, many of the rest are infected ; and the disease will show itself in the next generation, or descent of it ; if the year wherein it is planted prove a wet one.
  Weeds, and their seed, in the fields where they grow naturally, for time immemorial, come to as great perfection as ever, without change of soil.
  These weeds, with acorns, and other masts, crabs, sloes, hips, and haws, are thought to have been , originally, the only natural product of our climate ; therefore, other plants being exotics, many of them, as to their individuals, require culture, and change of soil, without which they are liable, more or less to degenerate.
  Equivocus, like his lower class of readers, which he describes, is unable or unwilling to distinguish the difference of change of species of plants, from the change of its individuals ; when he pretends to bring as an argument the degenerating of the individuals of beans, &c., to prove the necessity of changing the species of them.

  But to say, that the soil can cause wheat to degenerate into rye, or convert rye into wheat, is what reflects upon the credit of Laurembergius : it is as easy to believe, that a horse, by feeding in a certain pasture, will degenerate into a bull, and in other pasture revert to a horse again ; these are scarce of more different species than wheat and rye are : if the different soil of Wittemberg, and Thuringia, change one species, they may the other.
  Equivocus, font of every thing that has no foundation of truth, asserts, " that barley will degenerate into bigg," which is a very different species : and yet he doth not own from whence he stole this wonderful discovery.