Another important condition of the material is its state of dryness or moisture. It must not be too dry or the spawn will not run. In such cases there is not a sufficient amount of moisture to provide the water necessary for the growth of the mycelium. On the other hand, it must not be too wet, especially at the time of spawning and for a few weeks after. Some test the material for moisture in this way. Take a handful of the material and squeeze it. If on releasing the hold it falls to pieces, it is too dry. By squeezing a handful near the ear, if there is an indication of running water, even though no water may be expressed from the material, it is too wet. If on pressure of the material there is not that sense of the movement of water in it on holding it to the ear, and if on releasing the pressure of the hand the material remains in the form into which it has been squeezed, or expands slightly, it is considered to be in a proper condition so far as moisture is concerned for planting the spawn. WHAT SPAWN IS. The spawn of the mushroom is the popular word used in speaking of the mycelium of the mushroom. The term is commonly used in a commercial sense of material in which the mycelium is growing. This material is horse manure, or a mixture of one or two kinds of manure with some soil, and with the threads of the mycelium growing in it. The mycelium, as is well known, is the growing or vegetative part of the mushroom. Sometimes the word "fiber" is used by the mushroom growers in referring to the mycelium which appears in the spawn, or in the mushroom bed. The mycelium is that portion of the plant which, in the case of the wild varieties, grows in the soil, or in the leaf mold, in the tree trunk or other material from which the mushroom derives its food. The threads of mycelium, as we know, first originated from the spore of the mushroom. The spore germinates and produces delicate threads, which branch and increase by growth in extent, and form the mycelium. So the term spawn is rarely applied to the pure mycelium, but is applied to the substratum or material in which spawn is growing; that is, the substratum and mycelium together constitute the spawn. =Natural spawn or virgin spawn.=--This is termed natural spawn because it occurs under natural conditions of environment. The original natural spawn was to be found in the fields. In the early history of mushroom culture the spawn from the pastures and meadows where mushrooms grew was one of the sources of the spawn used in planting. The earth containing the spawn underneath clumps of mushrooms was collected and used.