The subject of this astonishing increase from a single plant thus became a topic for subsequent conversation and research. It being in Fred's line, he looked up several articles about weeds, undertook to extend the calculation, and arrived at results that almost frightened me. A single thistle would produce twenty-four thousand the first year, and five hundred and seventy-six millions the second! and we found that botanists had discovered in all other weeds an approximation to the same amazing power of reproduction. It must not be supposed, however, that every seed will vegetate. Animals and birds consume myriads of them, and other myriads perish under the extreme heat of summer and the equally destructive cold of winter. To some extent Nature thus confines the multiplication of weeds within limits. Botanists assert that these limits are prescribed, and that they cannot be passed. If it were not so, the seed of a single thistle would reproduce itself so rapidly as in a few years to cover with its progeny the entire surface of our planet. Our ground was singularly troubled with the rag-weed, which we found was immensely prolific. There were numerous other kinds also that came up all over the field, and it appeared to me that those which produced the most seeds threw up the rankest growth. What was greatly to their discredit, none of them produced a flower. So far as I could discover, they performed no other office than that of perfecting a crop of seeds for the sole purpose of next year producing another that would be many thousand times larger. Their stalks and foliage were rejected by cattle, and never came to much as fertilizers. It is probable they have some medicinal virtues, however, as the herb-doctors use them pretty freely. But I could regard them in no other light than nuisances in a strawberry-bed. So universally are weeds regarded as injurious to agriculture, that laws have been enacted to insure their destruction. In this country it has been made a finable offence to permit the Canada thistle to perfect its seeds. France imposes a heavy penalty on all who are in like manner neglectful of the common thistle. Every man in Denmark who fails to destroy the corn-marigold is severely punished. In the early history of Scotland, whoever "poisoned the king's lands with weeds, introducing thereby a host of enemies," was denounced as a traitor. Unhappily, with us there has been an abundant yield of both. As such instances show how these pests have been regarded by the agricultural world, one would think that it was now time for us to hear of their diminishing in number. But no such diminution can be asserted. The history of the migration of seeds is full of the most curious statistics. The reviewer of a recent publication makes the following interesting statement.