Plants having only very limited powers of choice as regards the matter absorbed by the spongelets, whatever is really held in solution by the water they imbibe must pass with it into the cell cavities, and in those oases where substances such as silex are taken up more freely by one plant than another, the difficulty depends probably on mechanical laws which, at present, we are unable to appreciate. If, however, the choice of the spongelets is limited, that of the stomates is still less so, so that whatever gaseous matter may be contained in the atmosphere will find a ready admission to the inward parts of the plant. It is obvious, therefore, that as the exigencies of plants are very different, and the same nutritive matter, or, rather, the same proportions of it, will not suffice for the maintenance of health in all, even under ordinary circumstances, disease may arise from a deficiency or redundancy of particular elements in the soil and atmosphere. The salt steppes of Asia produce only such plants as delight in the particular mineral which abounds in them, or are as able to tolerate it in such large proportions.

In land, again, over-manured with guano or other animal matters, health, or even vitality, cannot be maintained, where the proportion is such as to exceed greatly the wants of the species. Wheat, for instance, will not flourish where there is a total absence of silex, nor cabbages where the proportion of nitrogenous matter is very small. In some cases, indeed, superfluous matter which could never pass off by the stomates, is stored up in the cavities of the cells, as the crystals of oxalate of lime which form such a prominent and interesting feature in the leaf cells of figs, hops, and many other plants, the rhaphides with which so many vegetable cells are gorged, or the carbonate of lime in charads. There is no reason to believe that these matters are deposited with a view to any ulterior use, as is the case with the magazines of starch, etc., which are intended to perform important functions at some future and often distant period. Other matters, however, may be present in the soil or atmosphere which are never requisite for health in any proportion, and which in themselves may be destructive.

Different as vegetables are from animals in a multitude of respects, there are species which so closely resemble each other, that it is difficult to say to which great division of the organised world they really belong. Both these exhibit vital phenomena, ' and we may presume, therefore, that the principle of life, however it may be modified, is essentially the same in each. If proof, however, were wanting in other respects, the identity of the effects produced by many vegetable and mineral poisons upon plants and animals would alone be sufficient. Whether we take the principal organic poisons, as opium, hydrocyanic acid, chloroform, etc, or inorganic, as arsenic, hydrochloric acid, iodine, etc., we find that the effect produced is essentially the same, in some cases affecting the functions, in some the organic structure. Opium, hydrocyanic acid, chloroform, etc., paralyze or suspend the functions of vegetables, precisely as they do those of animals without injuring the delicate tissues; while arsenic, lead, etc, more or less impair their structure.

Nor is gaseous matter indifferent; the comparative barrenness of fens, at least as regards the majority of the natural order of plants, depends, in all probability, on the condition of sulphuretted hydrogen; the impure carburetted hydrogen of gasworks is notoriously injurious to trees, as is also the emanation from certain chemical works, which reduce their immediate neighborhood to a treeless wilderness. The mischief may, in many oases, be purely functional at first, but the suspension of functions, especially if long continued or often repeated, except where it is of the. nature of sleep, is apt to induce active disease, or the destruction of particular organs, which may in the end prove generally fatal.

It is, however, curious what concentrated poison some vegetables are able to endure. Moulds flourish in arsenical and other mineral solutions, which might have been supposed utterly incapable of sustaining any vegetable. One species is the source of great annoyance in electrotyping, as in the Map Office of the United States of Washington. The sulphate of copper is deprived of its copper by the mould, which assimilates the sulphuric acid while the copper is deposited as a thin, metallic pellicle on its walls. A fungus again flourishes in the water of tan-pits where no phaeogam could exist.

Though the action of many poisons upon plants, as opium, prussic acid, chloroform, etc, may be considered by the cultivator as mere matters of curiosity, which can never call for any especial treatment at his hands, it is most important that he should attend to the principle involved in them, for, if so, he will not over-manure his plants or trees. However beneficial the substance may be when properly administered, he will not use coarse, putrid manure as is the fashion with some, of treating vines, the most delicate, perhaps, of fruits, and the most easily impaired by injudicious treatment, nor will be be indifferent to the quality of air with which his houses are supplied. Ventilation will be of little use if poisonous vapors are constantly rising from beneath, and these are sometimes so intense as to produce at once visible evil.

It is very doubtful whether plants are capable of rendering ground noxious by excretion from their sound and entire roots. It is, however, easy to conceive that such plants as poppies, if ploughed green into the ground in considerable quantities, might prove injurious. - M. J. B., in Gardeners' Chronicle.

The following article is taken from a French paper: -

"Few people form an exact idea of the importance attained by many branches of our rural industry, such, for example, as the product of eggs. France sends every year to England about 7,780,000 kilogrammes of eggs, say 717,160,000 eggs, at a calculation of twenty-two for the kilogramme. Beckoning that a hen lays 100 eggs in a year, which is a fair average, it will be seen that this exportion is the produce of 1,711,600 hens. Our importations from other countries are only about 66,000 kilogrammes, and about the eighth of those sent to England are supplied by Belgium, and the Sardinian States. As for the consumption in Paris, it is not less than five or six millions of kilogrammes - that is to say, from 110 to 132 millions of eggs".

It will not be said there is not a demand, when it is proved that so many millions are consumed over and above what the country can produce. Our own poultry-keepers have a great advantage over foreigners. They have no freight, duty, nor expensive packing. Their market is always close at hand. A still greater advantage is, that the expense incurred by the foreign exporter, in collecting from Belgium and Sardinia, is just so much encouragement to ourselves.

The first idea that strikes us is, that, in many large farm-yards, many more fowls might be kept, without causing extra expense. Let us admit that the occupier is not a poultry fancier. A hen lays 100 eggs, and they are worth at least five shillings; a hundred hens will then pay, in eggs, twenty-five pounds. But, with care in selecting the breed and the birds, they may be made to produce more. We say nothing of food, because the fowls bred at a arm will more than pay any expense. Near a large town, where there is a demand for new-laid eggs in the winter, and at the commencement of the spring, they will realize much more than we have stated above.

We will say nothing of the other mode of making poultry profitable, as we have so lately treated of it. We desire only to call attention to the fact, that a great demand exists, that all the advantage is on the side of the home producer, while his inattention to it throws it into the hands of others who are more careful to look at small matters. - Cottage Gardener.