Ambury is a disease peculiar to the Brassica tribe, and is known by the various names of Hanbury, Anbury, and Club Root. Fingers and Toes, a name applied to it in some parts, alludes to the swollen state of the small roots of the affected plants.

Cabbage plants are frequently infected with ambury in the seed-bed, and this incipient infection appears in the form of a gall or wart upon the stem immediately in the vicinity of the roots. If this wart is opened, it will be found to contain a small white maggot, the larva of a little insect called the weevil. If, the gall and its tenant being removed, the plant is placed again in the earth, where it is to remain, unless it is again attacked, the wound usually heals, and the growth is little retarded. On the other hand, if the gall is left undisturbed, the maggot continues to feed upon the alburnum, or young woody part of the stem, until the period arrives for its passing into the other insect form, previously to which it gnaws its way out through the exterior bark. The disease is now almost beyond the power of remedies. The gall, increased in size, encircles the whole stem; the alburnum being so extensively destroyed, prevents the sap ascending, consequently, in dry weather, sufficient moisture is not supplied from the roots to counterbalance the transpiration of the leaves, and the diseased plant is very discernible among its healthy companions by its pallid hue and flagging foliage.

The disease now makes rapid progress, the swelling continues to increase, for the vessels of the alburnum and the bark continue to afford their juices faster than they can be conveyed away; moisture and air are admitted to the interior of the excrescence, through the perforation made by the maggot; the wounded vessels ulcerate, putrefaction supervenes, and death concludes the stinted existence of the miserable plant. The tumour usually attains the size of a large hen's egg, has a rugged, ichorous, and even mouldy surface, smelling strong and of-fensivelv. The fibrous roots, besides being generally thickened, are distorted and monstrous from swellings, which appear throughout their length, apparently arising from an effort of nature to form receptacles for the sap, deprived as it is of its natural spissation in the leaves. These swellings do not seem to arise immediately from the attacks of the weevil, for 1 have never observ-ed them containing its larva.

Mr. Marshall very correctly describes the form which this disease assumes when it attacks the turnip. It is a large excrescence appearing below the bulb, growing to the size of both hands, and, as soon as the hard weather sets in, or it is, by its own nature, brought to maturity, becoming putrid and smelling very offensively.

These distortions manifest themselves very early in the turnip's growth, even before the rough leaf is much developed. Observation seems to have ascertained, that if the bulbs have attained the size of a walnut unaffected, they do not subsequently become diseased. The maggot found in the turnip ambury is the larva of a weevil called Curculio pleurostigma. "I have bred this species of weevil," says Mr. Kirby, "from the knob-like galls on turnips called the ambury, and I have little doubt that the same insects, or a species allied to them, cause the clubbing of the roots of cabbages".

Marsham describes the parent as a coleopterous insect of a dusky black colour, with the breast spotted with white, and the length of the body one line and two-thirds. The general experience of all the farmers and gardeners with whom I have conversed upon the subject, testifies that the ambury of the turnip and cabbage usually attacks these crops when grown for successive years on the same soil. This 19 precisely what might be expected, for where the parent insect always deposits her eggs, some of these embryo ravagers are to be expected. That they never attack the plants upon a fresh site is not asserted; Mr. Marshall's statement is evidence to the contrary; but it is advanced that the obnoxious weevil is most frequently to be observed in soils where the turnip or cabbage has recently and repeatedly been cultivated.

Another general result of experience is, that the ambury is most frequently observed in dry seasons. This is also what might be anticipated, for insects that inhabit the earth just beneath its surface, are always restricted and checked in their movements by its abounding in moisture. Moreover, the plants actually affected by the ambury, are more able to contend against the injury inflicted by the larva of the weevil, by the same copious supply.

In wet seasons, I have, in a very few instances, known an infected cabbage plant produce fresh healthy roots above the swelling of the ambury. Mr. Smith, gardener to M. Bell, Esq., of Woolsing-ton, in Northumberland, expresses his conviction, after several years' experience, that charcoal-dust spread about half an inch deep upon the surface, and just mixed with it by the point of a spade, effectually prevents the occurrence of this disease. That this would be the case we might have surmised from analogy, for charcoal-dust is offensive to many insects, and is one of the most powerful preventives of putrefaction known. Soot, I have reason to believe, from a slight experience, is as effectual as charcoal-dust. Judging; from theoretical reasons, we might conclude that it would be more specifical; for, in addition to its being, like charcoal, finely divided carbon, it contains sulphur, to which insects also have an antipathy.

I have a 6trong opinion that a slight dressing of the surface soil with a little of the dry hydro-sulphuret of lime, that may now be obtained so readily from the gas-works, would prevent the occurrence of the disease by driving the weevils from the soil. It would probably as effectually banish the turnip fly or flea, if sprinkled over the surface immediately after the seed is sown. I entertain this opinion of its efficacy in preventing the occurrence of the ambury, from an instance when it was applied to some brocoli,ignorantly endeavoured to be produced in successive crops on the same plot. These had invariably failed from the occurrence of the ambury, but the brocoli was now uninfected. The only cause for this escape that I could trace was, that, just previously to planting, a little of the hydro-sulphuret of lime had been dug in. This is a very fetid powerful compound. Where dry lime purifiers are employed at gas works, it may be obtained in the state of a dry powder, but where a liquid mixture of lime and water is employed, the hydro-sulphuret can only be had in the form of a thick cream. Of the dry hydro-sulphuret I would recommend eight bushels per acre to be spread regularly by hand upon the surface after the turnip seed is sown, and before harrowing.

If the liquid is employed, I would recommend thirty gallons of it to be mixed with a sufficient quantity of earth or ashes, to enable it to be spread over an acre in a similar manner. For cabbages, twelve bushels, or forty-five gallons per acre, would not probably be too much, spread upon the surface and turned in with the spade or last ploughing. To effect the banishment of the turnip-flea I should like a trial to be made of six or eight bushels of the dry, or from twenty-two to twenty-eight gallons of the liquid, hydro-sulphuret being spread over the surface immediately after the sowing, harrowing, and rolling are finished. Although I specify these quantities as those I calculate most correct, yet in all experiments it is best to try various proportions. Three or four bushels may be found sufficient, perhaps twelve, or even twenty, may not be too much. In cabbages the ambury may usually be avoided by frequent transplantings, for this enables the workman to remove the excrescences upon their first appearance, and renders the plants altogether more robust and ligneous; the plant in its tender sappy stage of growth being most open to the insect's attacks. The warts or galls that so frequently may be noticed on the bulbs of turnips, must not be mistaken for the ambury in a mitigated form.

If these are opened, they will usually be found to contain a yellowish maggot, the larva probably of some species of cynips. This insect deposits its eggs in the turnip when of larger growth than that at which it is attacked by the weevil, and the vegetable consequently suffers less from the injury; but from some slight observations, I am inclined to conclude, that the turnips thus infested suffer most from the frosts of winter, and are the earliest in decay. - Johnson's Principles of Gardening.

The Ambury occasionally exhibits itself around Philadelphia, principally in small gardens, where the same crop is too frequently repeated: also in market gardens. In the latter case it may be attributable to the putrid manure used to produce excessive luxuriance. Lime, change of manure, rotation of crops, but above all deep tillage, bringing the subsoil to the surface, are the remedies adopted.