The opinions already expressed, respecting the dis eases of wheat, receive consalcrabli.: support limn what happened la,1 season, since the first edition of this work went to press. Tiat mildew acted, in minim ous in stances, as the destroiing age it of crop 1808, is univer sally acknowledged ; but that the defectiyeness of that crop was entirely oyving to in.ldew, nriy safely be ques tioned. In lac t, the chief injury proceeded from an unhealthy or pestilential atmosphere, at the time when the grain was in an embryo or imperfect state. Owing to that unhealthiness, something like abortion seemed to take place in the parent plant, after the fcetus of the young grain was formed, as was evident from more than one hall' of the cups, or vessels, prepared by nature for its reception, being totally void of substance, notwith standing that every part of the ear had blossomed equally well, and promised to furnish a numerous and healthy progeny. Even the grain which remained in life, proved afterwards to be of p...rlect or imperlect quality, according to the nature, situation, and condition of the soil upon which it was produced. Upon sound healthy soils, where the plants were provided with strong seminal and corona] roots, the grain was more deficient in quantity than defective in quality. In situ ations where abortion did not take place in the first in stance, the young grain, from receiving a regular supply of food, was enabled to resist the storms which beat upon and destroyed its weaker and worse supplied neigh bours. As happoes with persons of sound constitutions, disease was successfully resisted in many instances ; and though the healthiest plants had fewer grains in their ears than usual, being constantly defective in the upper part of the car, yet these grains whit It remained in life were ripened and harvested, after passing through the process of maturation, in the most satisfactory man ner.
It may now be inquired, how this abortion was brought about, which we have stated as so destructive to the wheat crop of 1808. This may be satisfactorily eluci dated by a reference to the weather, which prevailed through the months of July and August, as it is in these months that the diseases of wheat always appear, that of smut excepted, which is not generated by an Unheal thy atmosphere.
The month of July was excessively warm, more so than remembered by the oldest man living; and from the beginning to the 20th of the month, the slightest moisture, even in the mornings and evenings, was not perceivable. Owing to this uncommon heat, wheat plants upon all soils not composed of clay or strong loam, were, in a manner, at a stand with respect to growth, being enfeebled by the fierce rays of the sun, while any wind that blew was so sultry, that the evil was rather in creased by its effects. The ground, in consequence of this intense sun-shine, felt something like burnt-brick when taken from the kiln; of course, when the rains fell, smoke issued from the surface, something like what proceeds from lime-shells when water is thrown upon them; and this exhalation of vapour continued in a.
or lesser degree, till the soil was completely saturated with moisture, when the air became cooler and more temperate.
Under these circumstances, when putrid effluvia is sued from every pore of the soil, it was not to be ex pected that the wheat crop could escape from the danger with which it was encompassed. Apprehensions, there fore, were entertained, that the fields already in a sickly and declining state, would soon fall victims to the pes tilence which raged in the atmosphere, and the result soon showed that these apprehensions were too well founded. With the exception of the lands upon the sea shore, preserved, we presume, by refreshing breezes from the sea, every field was discovered to be more or less injured. Those soils composed of sand, soft loam,
and thin clays, mixed with peat earth, were almost, in every case, attacked with mildew, while the healthier and sounder soils, where mildew was rarely discernible, suffered considerably by having the young grain destroy ed in the cup, and, of course, yielded crops generally one-third or one-fourth short of the usual produce. had not thin or smooth chaffed wheats been generally sown, it is almost certain, that a single field would not have escaped mildew. We know of no field sown with the thick chaffed, or woolly eared varieties, that escaped mildew in its most aggravated shape. Even the smooth chaffed varieties depended for safety entirely upon the nature of the soil which they occupied, and their condi tion at the time when rainy weather commenced.
Here it may be remarked, that though mildew is a disease altogether unknown during dry weather, yet it is only in seasons when the weather has been very warm and dry that its effects are most strikingly displayed. In such seasons, rust often appears upon the straw of wheat, produced upon dry and light soils, and upon all soils which have not good stamina, brought on, it would seem, by the plants being stunted of nourishment. Now. if humid weather sets in when the plants are in this atrophical state, and continues for any length of time, the disease called mildew, which completely, checks the circulation of the plant, immediately follows, as was produced last season in numberless instances. In a word, had we been at the West Indies at the time, and learned that the weather from 24th July to 13th August was almost incessantly wet, we at once would have pre dicted that the wheat crop would be a failing one ; and on the truth of that prediction would have confidently relied, because similar ones, in the course of a pretty lengthened experience, had invariably been verified by the produce of wheat crops so circumstanced.
Some people have recommended the sowing of blight ed and mildewed wheat, because it will vegetate; though certainly the recommendation, if carried into practice, would be attended with imminent danger to those who attempted it. That light or defective wheat will vege gate and produce a plant, we are not disposed to con tradict; but that it will vegetate as briskly, or put out a stein of equal strength, and capable of withstanding the severe winter blasts, as those produced from sound seed, we must be excused for not believing. Let it only be considered, that a plant of young wheat, unless when very early sown, lives three or four months, in a great measure, upon the nourishment which it derives from the parent seed; and that such nourishment can, in no view of the subject, be so great, when the parent is lean and emaciated, as when sound, healthy, and vigorous. Let it also be remembered, that a plant produced from the best, and we ighticet seed, musk In ever} case, under a parity of other circumstances, have a stronger a onsti indult at the necessarily qualifies it to push on with greater energy w hen the season of growth ar rives. Indeed, the economy of nature would be over turned, had any other result followed. A breeder of cattle or sheep would not act more 'Oafishly, who trusted that a deformed diminutive bull or rani would produce hint good stuck, than the turn farmer does tvlio uses unsounn or imperfect seed. Without reasoning, how ever, on these matters, it may be stated, that we have seen fields whicn were partly sown with sound, partly with mildewed seed, and the difference was discernible at one glance through the whole winter months.