August 19, 1861. 
smooth silicious plaster, so hard as to resist the blow of a hammer; and the^first 
/ 
THE SCIENTJFIC MONTHLY. 53^ 
stomach is'complicated and has a long alimentary canal, while in the insectivorous 
species the stomach is simple and the intestines short, like the carnivora. 
In the United States all our bats belong to the insectivorous species, and are 
small in size. But in South America and the West Indies there are many large 
fruit-eating bats; in fact all the frugivorous bats are confined to tropical climates. 
Among the fruit-eating bats is the genas phyllostoma, peculiar to South America. 
In these the tongue is furnished with a row of wart-like protuberances at its outer 
extremity, .arranged in a circle, and forming a complete sucking tube, by means of 
which these bats are enabled to suck the juice of fruit and the blood of animals 
The vampire bat is a large species of the genus. Its natural food is insects, but i 
hard pressed it will suck the blood of poultry, cattle, and even of man. The blood is 
obtained entirely by suction from the capaillary vessels and not tlirough any wounds 
made by the teeth. The stories told by travelers of the bats destroying people at 
night by sucking their blood, fanning their victims into unconsciousness by the 
flapping of their wings, are highly exaggerated and fabulous. The vampire is 
entirely harmless, and not at all feared by the natives. Among other foreign bats 
is the genus nycteris, of Africa. In these bats the skin is extremely loose, and 
- fit certain points, and by a loose cellular membrane it is 
ground IS elevated as before, ana me spring nas lu move lorwara. inus it is 
compelled to travel round and round, discharging its silica and deepening the 
shaft in which it dwells, until finally, in the course of ages, the simple spring has 
produced this wonderful apparatus which has so long puzzled and astonished both 
the traveler and the philosopher .’’—Wonders of the Yellowstone. 
“ The time required for the construction of the Great Geyser has been esti¬ 
mated by Commander Forbes as ten or eleven centuries, on the following grounds: 
A bunch of grass, placed Under a little fall made by the ejected water, receives, 
in twenty-four hours, a coating of silica the thickness of a thin sheet of paper, or 
about one five hundredth part of an inch. At this rate it would take 1036 years 
to build up the 762 inches, which, according to his measurement, is the defJth of 
the tube. In evidence of the probable truth of this estimate, he makes note of the 
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