There are probably few branches of horticulture so ill understood as the management of seeds. A package of seeds may be placed in the hands of two men, divided between each, and sown by each in his own peculiar way; and while one succeeds in raising plants, the other fails. Sometimes the individual who succeeds in raising some particular seed one season, will himself fail in another, though to all appearances the seed was gathered, preserved, and treated exactly in the same manner. For want of attention to these variations and their causes, many erroneous notions respecting the vegetative powers of seeds have arisen, and many contradictory statements made by various writers, which needs only a slight reflection on the principles of successful seed-saving and sowing to reconcile. For instance, some old writer, I think Banbury, asserts that seeds of the Sweet Gum (Liquidambar ttyraciflua) will germinate the same season of sowing; while another old writer, I am not certain, but think Philip Miller, flatly contradicts this, satisfied that they will not grow under two years.

Succeeding writers have followed the one or the other, according to their own observations or taste; and to this day I am not aware that it is generally known that both are right to a certain extent I might instance many such cases. I could name a man in a western State, whose business* reputation is actually not in the highest observe that he had no difficulty in raising in the same season Peach trees from stones sown in the spring, without previously cracking them; and yet any man may do the same for himself, - he may raise either Sweet Gums or Peach trees in either one year or two, and yet in either case sow the seed in the spring of the year. We have only to understand two things: 1st, What preserves the vitality of seeds? 2d, What induces their germination?

The vitality of seeds is an interesting study. There is probably no inherent reason why any kind of seed may not be preserved sound to an indefinite period. Wheat and other cereals which have been taken from E+gyptian tombs and monuments, in which they had been enclosed hundreds of years, have readily germinated. In newly plowed-up pastures, which may have lain unbroken many years, we constantly see myriads of Rag-weed (Ambrosia artimesiafolia) springing up from seed which must have lain dormant during that period. The St. John's wort (Hypericum perforatum), Hedge Mustard (Sisymbrium officinale), and the Wild Carrot, are also familiar examples, puzzling to many of our "farmers," who can scarcely be made to believe that they are not "natural" to the soil, springing spontaneously and equivocally therefrom. It is recorded that in some countries the Sinapis arvensis, a kind of Mustard, most generally springs up in clay taken from very deep wells; and a few years ago I saw it stated, in one of our Patent Office Reports, that the Great Yellow Mullein ( Verbas-cum thapsus) commonly made its appearance after fires on the prairies.

Yet the seeds of all the plants I have mentioned, under ordinary circumstances, germinate in a few weeks, and some of them even in a few days after sowing.

There is another class of seeds which preserve their vitality to irregular periods, without any extraordinary intervention. The seeds of the Cucumber and Melon will keep fresh so long, that gardeners say the longer they are kept, the better they are; which, if true, would render them of remarkable value by "the end of the world." Nevertheless, they certainly will keep fresh a great many years. The Turnip, the Balsam, or Lady Slipper of Philadelphians, and the Parsley, are instances of easy vitality, though of a few years less than the Gourd tribe; while the Onion, Spinach, or Lettuce, will seldom germinate over one year.

In all these cases, their preservation is owing to their not being in a position to admit of the mechanical action of heat and moisture in preparing their integuments, or outer coverings, for the chemical action of the elements conducive to germination - an explanation that will be better understood after we examine what induces germination. It will be sufficient here to remark that the vitality of seeds is entirely dependent on this relative position of heat and moisture. Some seeds require more moisture than others to tempt them to germinate; others must be indulged with more heat than water, in comparison: but every kind of seed requires its own due proportion of each. Seeds of many plants, as the Water Lilies, will only grow in water; and of these, some, as the Victoria, must have an accompanying degree of heat of over 70° while our Yellow Pond Lily will germinate at 55°. Other plants, as the Balsam Thunbergia, Globe Amaranthus, etc, will readily grow in comparatively dry soil.

In this class the same difference in the required degree of heat is apparent as in the class; for while the Indian Mallow (Abutilon avicennae) will not germinate unless accompanied by a heat of over 60°, the garden Speedwells (Veronica arvensis, V. Buxbaumii, V. serphylloefolia, etc.,) will readily appear through the soil with the heat anywhere above 32°.

A knowledge of the separate requirements of each seed constitutes practical talent, and this can not be acquired without extensive experience and observation; but, a few principles can be derived from these, which will do much to simplify the labors of those who have to go over the same ground.

I have said that heat and moisture act mechanically in the process of germination, and they do so in this manner: On the application of heat, the pores of the skin are expanded in the outer case or husk of the seed; into these pores moisture is admitted; and then commences the chemical action which is to effect its germination. An element of the water, which chemists call oxygen, seizes on one of the elements of the husk, carbon, the charcoal principle, and forms a new combination, and disappears in the shape of a gas, carbonic acid, one of the chief sources of food for the young plant as soon as it shall have produced perfect leaves. As soon as this combined force has eaten its way through the husk, it has to perform a similar duty for the "kernel" inside. When this portion of the seed has been in like manner operated upon, it receives its commission to go forth, increase, and multiply, and in short take upon itself all the duties and responsibilities of a living plant "But you have said nothing about air. Heat, air, and moisture, are frequently written of in treatises on germination. What office does air hold in the process "None whatever, my good friend. Air is a positive injury in the case, though of immediate importance directly after the pushing of the embryo.