COMMON MUSHROOMS OF THE UNITED STATES 



399 



acid that crumbles the hardest rock. 

 Rains wash the disintegrated particles 

 into cracks, crevices, and crannies down a 

 slope. The remains of the dead lichens 

 are added to the debris to form the first 

 beginnings of soil in which other lichens, 

 small ferns, and seed plants find a place 

 to thrive and eventually die, each plant 

 leaving behind some small particles of 

 matter. Gradually, with infinite patience, 

 Nature thus deposits soil in the valleys. 

 Ages of this slow but cumulative work, 

 in which soil bacteria and other fungi 

 play an essential role, and we have rich, 

 virgin soil ready to receive the precious 

 grains of wheat. Then the eye of hungry 

 man is gladdened by the sight of acres 

 of the golden crop. 



FUNGI RAISE THE DOUGH 



Bread made from unleavened dough is 

 not to the taste of most of us. It must 

 be light and spongy to be palatable. To 

 obtain these qualities we are again de- 

 pendent on the fungi. The good house- 

 wife buys yeast, dissolves it in water, and 

 adds the fluid to the heavy dough, which 

 is then thoroughly kneaded and set aside 

 overnight in a suitable temperature. The 

 next morning she is pleased to note that 

 the dough has risen. After further 

 kneading, it is placed in the oven and 

 baked into appetizing loaves. On being 

 cut, the bread exhibits a multitude of 

 small bubbles of nearly equal size. 



The little Brownies that labored while 

 others slept are microscopic fungus cells 

 that were introduced with the yeast. 

 Given sugar, starch, moi'sture, and warmth, 

 these ' cells multiply with incredible ra- 

 pidity, at the same time giving off carbon- 

 dioxide and another product. The car- 

 bon-dioxide gas collects in bubbles, and 

 thus distends and lightens the dough. 



If bread be left in a moist place it will 

 mould. Here, too, we have fungous ac- 

 tion. 



Moulds, like bacteria and yeast fungi, 

 are ever present and ready to alight and 

 feed upon organic substances suitable to 

 their taste. Roquefort cheese owes its 

 flavor to a certain mould. Another is. 

 known to plug up the human ear. 



Some of the industries in which the 

 action of the ferment fungi is essential 

 are: The making of buttermilk and 

 cheese, the tanning of leather, tobacco- 



curing, the fermentation of vegetables 

 (sauerkraut, fodder in silos, etc.), all 

 bread-making where yeast is used, and all 

 fermentation processes in which alcohol 

 is produced. 



FUNGI DESTROY WHEAT, TREES, AND WOOD 



In 1916 the black-stem rust destroyed 

 in the United States and Canada 280,- 

 000,000 bushels of wheat. Add to this a 

 15 to 25 per cent reduction of the barley 

 and oats crops, and we become aware of 

 the appalling destruction that a single 

 fungous disease can cause. 



One of these, Endothia parasitica, 

 threatens with extinction the glorious 

 chestnut trees of our eastern coast. The 

 disease caused by this fungus fiend, the 

 chestnut bark disease, starting in the vi- 

 cinity of New York City about 1904, 

 spread rapidly as far north as New 

 Hampshire and south to Virginia. In its 

 devastating march it has destroyed tim- 

 ber valued at more than two hundred 

 million dollars, and the end is not yet. 



Another disease, the white pine blister 

 rust, though not yet as widely known 

 as the chestnut disease, is likely to be- 

 come so uhless preventive measures are 

 adopted anct cooperatively carried out by 

 the States concerned. 



While the destruction of living woody 

 tissues is steadily going on in the forests, 

 dead wood, including that used in build- 

 ings, railroad ties, etc., is likewise being 

 destroyed by species that specialize in 

 saprophytism or scavenger-work. 



ANTS "CULTIVATE" MUSHROOMS 



The almost human sagacity of the ant 

 has interested man from earliest times. 

 Isn't it possible that Homer called the 

 Thessalian legions "myrmidons" because 

 they swarmed like ants and fought with 

 the cunning and bravery of these insect 

 warriors ? The foresight exhibited by the 

 ant in storing its food, furnished ^Esop 

 with the theme for one of his most de- 

 lightful fables. Later, upon closer obser- 

 vation, we were startled to learn that 

 Mr. Ant is also a good "dairyman,"* 

 milking his "cows" whenever he wants 

 "milk" ; but it was not until recently that 



* See ''Notes About Ants and Their Resem- 

 blance to Man," by Dr. William Morton 

 Wheeler, in the National Geographic Maga- 

 zine, August, 1912. 



