There are some brands of spawn, that is, those manufactured by certain houses, which rank very high among those who know the qualities and the value of good spawn. Some large growers send direct to the manufacturer for their spawn, and where it is to be obtained in large quantities this is a desirable thing to do, since the cost is much less. Where obtained from seedsmen in large quantities, the prices are much lower than where small quantities are purchased. One of these brands of spawn, the Barter spawn, is for sale by several different dealers, by Mr. H. E. Hicks, Kennett Square, Pa., by Henry F. Michell, 1018 Market street, Philadelphia, and by Henry Dreer, 724 Chestnut street, Philadelphia. Another brick spawn, known as "Watson Prolific," is for sale by George C. Watson, Juniper and Walnut streets, Philadelphia. James Vicks Sons, Rochester, N. Y., and Peter Henderson & Co., New York City, have their spawn manufactured expressly for their trade. The Barter spawn is said to be made fresh every year, or every other year. Instead of the "continued culture" of spawn, that is, inoculating the bricks each succeeding year from the same line of spawn, which is, as it were, used over and over again, a return is made each year, or in the alternate years, to the natural or virgin spawn, which is obtained from old manure heaps. In this way, the Barter spawn[D] is within two to three, or four, generations of the natural spawn. The number of generations distant the brick is from the natural spawn, depends upon the number of times it may have been multiplied before it is inoculated into the bricks. That is, the natural spawn is probably first grown in large beds in order to multiply, to produce a sufficiently large quantity for the inoculation of the immense number of bricks to be manufactured. For it is likely that a sufficient amount of natural spawn could not be obtained to inoculate all the bricks manufactured in one year. If a sufficient amount of the natural or virgin spawn could be obtained to inoculate all the bricks of one year's manufacture, this would produce a spawn removed only one generation from that of natural spawn. If the natural spawn were first grown in beds, and from here inoculated into bricks, this particular brick spawn would be removed two generations from the natural spawn. So the number of times that successive inoculations are made to multiply the spawn, the manufactured products are removed that many generations from the natural spawn. Where recourse is had to the natural, or virgin spawn only once in two years, the second year's product would then be further removed from the natural spawn than the first year's product. Where we know that it is removed but one or a few generations from the natural spawn, it is a more desirable kind. For the nearer it is to the natural spawn, other things being equal, the more vigorous the mycelium, and the finer will be the mushrooms produced.