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matural Ibistor^ IRotes. 



Multiplication of Ophioglossum.— It results from the observa- 

 tion of Mr. G. Poirault that the Adder's Tongue Fern {Ophioglos- 

 sum) is never reproduced from its spores, but that it is propagated 

 exclusively by buds that form on its roots. 



Effects of Cold upon Animals.— In a paper read to the French 

 Academy of Sciences, M. CoUn discusses the action of cold on 

 animals. The rabbit endures considerable cold. Adults have 

 lived in ordinary hutches suspended from the branch of a tree or 

 standing on a heap of snow, and their temperature has only been 

 lowered about one degree in five or six days, when the outside 

 temperature varied from lo'' to 25° C. Sheep and pigs are also 

 able to live through severe weather, but the dog and horse are 

 killed by it. 



Pliny and the Ants of North America.— In Pliny we find the 

 following passage in regard to a certain species of ant : — "Among 

 the Northern Indians, called Dowdes, there are certain ants that 

 extract gold from the Jiiines. . . . This metal, which they extract 

 in winter, the Indians rob them of in summer, while the ants are 

 hidden in their tunnels because of the heat." 



This passage having struck us by its clearness, says M. Ver- 

 coutre (in Rivue Scientijique), we have been led to ascertain 

 whether the assertions of Pliny are accurate, and, if so, what were 

 the ants that he had heard spoken of. Now, we have found that 

 there exists a particular species of ant that engages in this sort of 

 mining, and that it is the Pagonomyrmex occidentalis studied by the 

 Rev. H. C. McCook. 



These ants, in fact, after they have finished the hillock that 

 serves as a dome to their galleries, cover the whole with a sort of 

 mosaic work formed of fragments of rock, fossils, ores, etc., which 

 they obtain through a regular mining operation at a considerable 

 distance beneath the surface of the earth. As in the country 

 where these ants are met with it happens that the subsoil is often 

 an auriferous deposit, it will be conceived that the roofing of the 

 ant-hills is frequently composed of spangles of gold, which, washed 

 by the rains of winter, are in the fine season easily recognised and 



