the preceding, bore one quart of balls in 28 hills; and yet, whether you regard its foliage or tubers, its vigor was little above our old sorts, and by no means equal to that of the family to which it belonged. (8.) The old Kidney potato was one of the first to feel disease, yet it bears a little seed almost every year upon a few scattering hills found among my field crops. These facts are not easily harmonized with any theory. A variety of potatoes cannot reasonably be expected to bear a heavy crop of balls and tubers at the same time. Both balls and tubers are the result of elaboration in the foliage. The material thus elaborated is derived from the air and earth. Now, if in a given position one variety bears a heavy crop of sound tubers, it is not to be expected that another variety should do the same, and also yield a heavy crop of balls-since, in the last case, the draught made upon the elaborating energy of the plant must have been at least double that of the other; and as the seeds of all plants always contain more mineral ingredients derived from the soil than simple wood, bulbs, or tubers, so, in the case of large crops of potato balls, there is proportionably larger quantities abstracted of important material from the soil than in the case of a simple crop of tubers. No one expects that, during the same year, a tree should make a stout growth of new wood and also of fruit. Unquestionably, the stripping off of the very young balls, or, better, of the flowers, would add, in the case of varieties given to bearing, heavy crops of balls to the crop of tubers. But whether this labor would prove profitable in the end is a question not readily settled, depending on the price of labor, &c. May it not be suggested as probable that in the native land of the potato, where the season of vegetable growth never ceases, the seed balls and tubers are matured successively? My Chili potatoes of 1851 bore enormously this year. These balls matured at least the early sets, which comprehended nearly the whole crop-before the tubers were set, and they were actually gathered in the last four days of August; in the month succeeding, the tubers were mainly produced. Now, suppose this variety could have grown until the first of November, as it doubtless does in most places where the potato is a native, it might have exhibited a large crop of tubers, also; as it was, they were sufficiently numerous, but small, although the vines. were green until killed by frost. Perhaps we have, among our hardy trees and plants, some analogical proof of this sentiment. While a large part of our fruits form bearing wood and fruit in alternate years, others of them produce them in ditferent parts of the same season. Thus, the raspberry, blackberry, currant, gooseberry, strawberry, tulip, hyacinth, &c., seem in a good degree to form their flowers and fruits in the early part of the season; while the fruit bearing wood for the next year, the bulbs and runners, are formed in the latter part of the season. So the plum, peach, and other stone-fruits form their stones in the early part of the summer; while the mere pulp, whose formation makes a much lighter draught on the soil, is formed later in the year. It is familiar to every gardener, that the draught made on the energy of a plant to form the pod, and almost the full sized berry of the bean and the pea, is much less than that necessary to give them maturity; hence, if the first sets of beans and peas are permitted to ripen upon the vines, the plant, in most cases, soon dies; while if they are plucked green for market, the plants of most varieties will set a second, and even, in some cases, a third crop of fruit. We need light on the natural history of the potato; and it is desirable that a State, that for eight successive years has suffered a loss, directly and indirectly, of about half a million of dollars annually by the disease of the potato, should take some efficient means to gather information on this subject. An agent sent to South America, to travel in the native region of the potato for one or two years, might gather rich materials in the study of its natural history. 6. The liability of the potato to rot not always proportional to its weakness.-A sort which, from its weakness, yields readily to morbid influences, may lose its foliage so suddenly as to hinder the transmission of the morbid circulation to the tubers. In this case, the tubers will usually be sound, though, if the attack were early, they will be small. In the case of a sort considerably stronger, but not entirely hardy, the disease will be less rapid and more lingering. In this case, the crop will be larger, but the tubers will be more or less diseased. Had a man just two such varieties of potatoes, it would be a difficult question to settle which of them he should plant. 7. The disease of the potato not specific.-Some diseases-as measles, whooping cough, small pox, &c.-are specific; they have a fixed type. Their severity may vary with personal constitution, season of the year, and atmospheric influences; but they have a positive, unmistakable character. On the other hand, such affections as common colds, dyspepsia, and rheumatism have not this specific character; certainly not in their incipient and lighter manifestations. Their existence may be often questionable. Now, the disease of the potato may be compared with this latter class of diseases. It being the result of an infelicity of weather, may exhibit any degree of severity, and end with every variety of result-from that which withers a few leaves of the foliage to that which blackens it, as with sudden frost, or to that which more gradually destroys the whole crop. If this position be true, it obviously follows that the disease admits of no specific remedy. We must improve the constitutional energy of the race, so that it will meet ordinary atmospheric influences without substantial injury. In one aspect of the disease, it suffers with all other tropical plants cultivated here; in another, it suffers in common with most hardy plants. Both aspects of disease are explicable on the common principles of physiology. I doubt not that we should find, could the history of agriculture be accurately written for the period of the past century, that frequent traces of this disease. would be found at various times. With just as much certainty I should expect that traces of it would be found on the Andes, and where the potato grows indigenously. 8. Disease does not ordinarily communicate from the injured to the strong tuber. In the autumn of nearly every year, for three or four past, I have stored partially diseased tubers with those that were strong-the small culls of my market potatoes. They were all designed for feeding to stock; often a portion of them have remained until spring. They have then been found a mingled heap of small sound potatoes in a pulpy, rotten mass. Had the heap been large enough to heat, doubtless all would have been lost. The fact is, the potato has a less permeable skin than any other culinary root. This impermeability forbids the "transmission of ordinary liquids through it; hence it is the last root to wither in the sun, and the last to absorb moisture. The withering of potatoes, in ordinary cases, in the spring, is the result, not of the transpiration of their juices, but of their loss by germination. 9. New modification of disease.-I have a new seedling in the family of my home varieties; it is quite hardy in foliage, has a very upright growth, yields well, and is a good tuber for the table. On digging, it exhibited a diseased condition entirely unlike the pervading one. It consisted in a small, wet, rotten spot on the end of the tuber, where the stolon was inserted; it extended, perhaps, to one-fifth of the whole crop of the variety. On cutting it off, the tuber seemed to heal naturally, and the injury was small. This variety grew late; perhaps the injured part was the result of morbid decomposition amid the damps and chills of autumn. 10. The value of green-sward soil for potato crops. (1.) It affords, as it gradually decomposes, the most natural nourishment of the potato. (2.) It is a slow conductor of heat, and so preserves an equable temperature about the root. (3.) It preserves moisture in the soil. (4.) It forms a loose mass, in which the tubers may readily form. Coarse manure subserves all these purposes, but in a much less perfect and economical manner, and, while the potato is weak, in a manner much less safe. 11. Mode of securing the best tubers for seed.-Besides the frequent renewal of the potato from the seed ball-a thing never long to be neglected-something may be done to continue the vigor of existing valuable varieties. (1.) Let every cultivator plant a small plat for seed in good medium. soil and fair exposure; thus he will be likely to secure tubers of the highest health. (2.) For ordinary winter stores such seed may be planted in some. what richer soil. The forcing of it by a richer cultivation, for one season, will not be likely to enfeeble it sufficiently to disease it much, while the crop may be large. (3.) Another portion of seed may be planted in very rich soil, where it may yield a very heavy crop for early market; but it will be likely to be sold and eaten before any morbid tendencies which such a course of cultivation might produce would be likely to be developed. None of these last should be used for seed. 12. A seeming anomaly.-A variety planted very early will sometimes mature safely, when the same sort, planted later, so as to fall under the influence of bad weather, will be diseased. So, also, when disease comes very early, a late growing variety may just escape morbid influences, which come early, and, when better weather comes, mature sound tubers. 13. The general improvableness of the potato, by reproduction, being admitted, what is the probability of success in a given case?-The answer undoubtedly will be, that success will be in proportion to the elevated point from which you start. There will always be a tendency in like to produce like. (1.) Suppose you start with a foreign sort whose first and leading quality is hardiness-one whose flesh, perhaps, is yellow and heavy, and whose maturity is late: the seed-balls of such a variety will produce a family of seedlings the most of which will be hardy, though few will be highly improved in quality of flesh and time of maturity. They will need, therefore, a second or third reproduction. (2.) Suppose you start with seed-balls from a home variety which possesses fine shape, color, and white and dry flesh, but is deficient in hardiness: the result from such seed-balls will probably be a family of seedlings which will resemble the parents in all leading qualities, and some few of which will, moreover, exhibit a fair improvement in hardiness, though still needing a second or third reproduction from the seed ball. (3.) Suppose the case of a variety, either imported or long cultivated at home-one that possesses a combination of all good qualities. Here it should be remembered that these qualities, particularly hardiness, will one day wear out. It should, therefore, he reproduced from the seedballs, even though you continue to cultivate the original variety for many years afterwards. In the case of a family of seedlings from such a variety, you may expect to get, proportionably, a very large number of seedlings of good quality the first time you sow seed. Such are the results of my short experience. The proofs of these positions will be seen, or inferred, to a considerable extent, in the article to which this is an appendix. 14. On the possible occurrence of potato disease in the native clime of that plant. (1.) The potato disease is reported (see Report of the Commissioner of Patents for 1847, pp. 141, 142) to have occurred at Bogotá, in New Granada, and in Peru. This asserted fact is supposed by some to be inconsistent with any and all explanations of the cause. This inference, however, is contradicted by undoubted analogical facts; while it tends to discourage all further examination of the subject. (2.) The general laws of vegetable physiology are alike applicable to all climes. (3.) Climate, also, however benignant and uniform it may usually be in a particular place, is not unchangeable. In a portion of France, near Strasburgh, as emigrants have informed me, a succession of unfavorable seasons, within the period of the present generation, so far discouraged the culture of the grape that it was almost entirely abandoned, and was not resumed until recently. The olive, also, was once extensively cultivated in the south of France, but in the hard winters of 1709, 1766, 1787, 1789, and 1820, it was almost totally destroyed. Now, instead of raising a tolerable supply from the country, large quantities are imported from Spain. (See Kenrick's Orchardist, under the word Olive.) Other and simular cases of failing vegetation, under occasional severities of the weather, are common in the annals of agriculture and pomology. (4.) The potato disease has been shown to result from severities of weather, according to well ascertained physiological laws. When it has grown old, and is subjected to too stimulating a course of culture in a climate that was never quite congenial, it becomes diseased in foliage, and also often in tuber. (5.) Now, suppose that in the native region of the potato the usual steady temperature of the climate is interrupted by chills, rains, and lacerating winds, then, by every consideration of permanence in physiological principles, disease ought to be the result. So, also, should the damp and hot weather that is common in the plains, below the common location of potato culture there, invade the higher regions on the mountain plains, the same result must follow. It will be said that in a climate noted for its great mildness and uniformity, such changes, and of course such consequences, would not be likely to occur. True, most true; but who will undertake to say that, with such and similar facts occurring in the history of other plants, and standing out on the page of agricultural history, the thing is impossible. And when they occur, like causes must produce like effects. It should not be forgotten, moreover, that in the mild and genial climate of the Andes, many varieties of potatoes are probably cultivated that would not bear the climate here at all. Such varieties would be likely to suffer under slight severities-such, for instance, as our common varieties would pass through uninjured. These varieties would be the first to suffer there in a season in the least degree incongenial, and this suffering would be sufficient to establish the fact of the occurrence of potato disease there, the relative malignity of which we here could not judge in our ignorance of all the facts in the case. 15. On the relative tendency of moist and dry soils to produce seed balls. (1.) The yam and four varieties of Chili potatoes, imported in 1851, bore seed-balls equally well on moist and dry soils. There was at the same time but little difference between the two positions in foliage and tubers. (2.) Of my many sorts of Bogotás-both the original importations of 1848 and the numerous seedlings of 1849-none bore seed on the moist ground, though the health of the foliage and tubers was equal in the two positions. 16. On the difficulty of getting valuable new varieties of potatoes by importation and reproduction. The attempt to improve the potato is not It must be made ordinarily with much labor, patience, and an easy one. skill. (1.) The reproduction should be made on an adequate scale, since, in the case of seedlings from a home variety, but few out of hundreds will combine every good quality, especially hardiness, at the first time of reproduction. So, also, in the case of seedlings from a foreign sort, though most will be hardy, yet few will combine all other good qualities short of a second reproduction. (2.) So, in importations from a foreign land, not only will there be much expense ordinarily, but, as the imported tubers will come from a great variety of climates, it may be, that out of numerous hardy sorts no one will be found exactly fitted to this climate, in its time of maturity. Out of nine varieties noticed above, I have found but one certainly, another with some probability, fitted to all the requirements of this elimate. 17. Potato discase not mysterious.-Leaves are the means of elaborating the juices of the plant. The quantity and quality of their elaboration will determine the quantity and quality of the crop. If the leaves are early destroyed, before the tubers of the potatoes are fully grown, they cannot be expected to increase subsequently to that destruction. So, if the leaves are diseased to any extent, the elaboration will be unhealth |