Page:Popular Science Monthly Volume 50.djvu/589

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571
FRAGMENTS OF SCIENCE.

serted stone quarries. The people who cultivate them are said to practically live underground, and are called champignonistes. The beds are made as follows: A dry and clean place near the mouth of the cave is selected. The spot is covered with manure, which is allowed to lie undisturbed for several days. The manure is then thoroughly worked over, all foreign matter being removed, and then beaten and pressed down into shape. After about a week the process is repeated and the beds are watered. At the end of another week the surface will be brown and fermentation very active. At this stage the first turning must be repeated, when the mass is again allowed to rest three days. It should then be soft to the touch, but leave no moisture upon the hand. The temperature requires to be carefully watched, and the first heat of fermentation must be allowed to pass off before the blanc or spawn is sown. After the spawn is planted the beds are covered with a thin layer of prepared earth called goptage, kept well watered, and in about forty days the mushrooms will appear. A bed will with proper attention produce a continuous crop for three months. The seed, spawn, semence, or blanc (mycelium) is usually supplied by the market gardeners from old melon beds. It is sold in the shape of a brick or cake, which, if placed in a dry, airy place, preserves its vitality for several years. The annual crop of mushrooms in France is valued at about two million dollars.

 

Caviare in Russia. — In Russia fish plays a very important part in the economy of life. On fast days, of which there are so many, it is an indispensable article for the whole nation, and on other days many of the people, who are too poor to buy meat, depend on fish as their only animal food. Russia's numerous rivers and extensive coast line make fish a cheap and common food there. The most valuable products obtained from fish in Russia are cod-liver oil and caviare; the latter coming mainly from the sturgeon. The United States consul at St. Petersburg is given as authority for the following description of the preparation of caviare: The roe is taken out of the fish, and the egg bags in which it is inclosed are removed by rubbing the mass on a sieve; the eggs pass through the meshes, while the skin does not. When fish are in the first stage of decomposition, the egg skins get so soft that they can be readily separated from the roe, and from these the low grades of caviare are made. The caviare is next placed in brine. The difference between the so-called fresh caviare and the ordinary material put up for keeping or export consists in the longer or shorter time it is allowed to remain in the brine, and also on the strength of the latter. Immediately after the eggs have been rubbed through the sieve, they are put through the brine, and as soon as they are deprived of the superfluous salt, are placed in tin jars or cans and small wooden kegs, and the so-called fresh caviare, which is high priced, is ready for market. The cheaper kind is cured in the brine and then put into linen bags and pressed. This is called pressed caviare. During ten months of 1895 Russia exported 4,658,448 pounds of pressed and 613,904 pounds of fresh caviare.

 

Venomous Fishes. — In many seas, especially those of the tropics, are found fish provided with a poison apparatus, which consists usually of a spine or spines more or less erectile in character, and connected with a poison gland. Prof. James D. Brunton gives an interesting account of two of these fishes, the Trachinis draco and Scorpœna scropha. They are only poisonous as a serpent is poisonous — i. e., by wounding; their flesh is good and wholesome. Although the fish differ widely in appearance, yet the poison produces the same effect. The Trachinis draco is a hand-some fish, not unlike a trout in general appearance. Upon each of its gill covers is situated the spine, connected with its poison gland through a duct formed by the combination of a groove in the spine and a very thin membrane, which covers the latter almost to its point. When the spine enters a resisting body, the membrane is pushed back, allowing the poisonous secretion free access to the wound. The gland is small, with nucleated colorless cells secreting a transparent fluid. The Scorpœna, on the other hand, is an unattractive-looking fish, squat of body and having a large, misshapen head. It may attain a large size, and is called by the French fishermen "le diable." The special organ in this fish is connected