COSMIC EXCHANGE OF MATTER AND LIFE 437 



possible life would thus be simply annihilated. The objection 

 was not in the least valid. It is now known that in the brief 

 moment of its flash through the air only the surface of the 

 meteorite is fused ; when the interior temperature can be 

 measured soon after its fall to the earth, it is found to be 

 astonishingly cold, just as our supposition regarding the cold 

 of space would require. A much more serious difficulty lay in 

 our later-gained knowledge of the meteorites themselves. It 

 is not at all clear that they are chips of shattered planets from 

 far-off systems. 



But in the suggestive paper already referred to, Die Ver- 

 breitung des Lebens in Weltenraum, 1 Arrhenius has given this 

 extramundane theory a new and very plausible form. The 

 distinguished Swedish compeer of Kelvin and von Helmholtz 

 points out that we already know of life-germs less than a 

 quarter of a micron in diameter ; and since there exist several 

 bacterial diseases wherein the germ is apparently too small for 

 microscopic detection, we may suppose other germ forms yet 

 more minute. Smaller still must be their spores or seed-like 

 granules, with resistant envelopes, which the bacteria throw 

 off, and to which their continued existence is due. 



Many of the bacteria we know float in the air ; so much the 

 more must the spore germs. It is easy to see how they might 

 be carried up by air-currents into the higher levels of the 

 atmosphere. It is Arrhenius' interesting suggestion that from 

 there they might be driven off into space perforce of electrical 

 repulsions. 



It has been for a long time known that the earth possesses an 

 electrical " charge," that bodies or particles will be attracted to 

 or repelled from it just as, let us say, bodies of paper are 

 caught, up by a glass rod when the rod is rubbed up smartly. 

 The globe is in a way a vast electrical " field," which by times 

 say, upon a clear, snappy winter morning may attain con- 

 siderable intensity. 



We have come in later days to know that there is a unit of 

 electrical charge, or, as we might say, an electrical atom. When 

 a body is " electrified " it is, as it were, covered with these 

 electrical atoms. This unit charge may be sustained by very 

 minute bodies as well as by larger ones. It is not a function of 

 surface or mass. It follows, therefore, that we may conceive of 

 1 Die Umschati, June 13, 1903. 



