GEOLOGY. 683 



site of the same family, the Isaria of the sphinx, has hith- 

 erto only been observed on certain nocturnal moths. The 

 chrysalides and larvae of these are never attacked by it ; 

 other species infest them. Unless one possessed the imagi- 

 nation of a Bonnet, is it possible to suppose that nature 

 would uselessly have burdened the air of the whole globe 

 for the mere purpose of scattering seed on the bodies of a 

 few spiders and moths, and that there was always a stock 

 ready for the perfect insect, its chrysalis, and its larva ? 



Still more curious facts are known ; for instance, that of 

 a fungus never found but on the neck of a caterpillar of 

 tropical countries. It is always solitary on this, and of enor- 

 mous size in proportion, being often four to five inches high. 

 In this fortuitous case, is the air necessarily choked with 

 seeds in order that from time to time one may be planted on 

 a particular spot not more than a square millimetre (.00155 

 square inch) in extent? 



As a particular vegetation is present in every form of 

 fermentation, its germs, according to the panspermists, must 

 have floated loose in the atmosphere from creation up to 

 the time when any new fermented liquor was discovered. 

 Did they rest so many ages unoccupied, awaiting the mo- 

 ment when Osiris invented beer? And even now, does the 

 atmosphere, loaded with these little seeds, drift them from 

 pole to pole, till the Greenlander or Patagonian sets to work 

 to brew a few quarts of this drink, or till it can fecundate 

 the new ferments which each chemist may invent in the 

 silence of his laboratory ? 



If it really were so, we might groan over the fate of the 

 atmosphere ! 



