GEOLOGY. 721 



We find atoms of food, of our clothes, of our furniture, and 

 of our dwellings, everything in short is represented there. 



The flour of wheat, which constitutes the basis of our 

 food, and is used everywhere, is disseminated everywhere 

 by the air. By means of this fluid it penetrates into the 

 most secret recesses of our dwellings and monuments. I 

 have discovered it in the most inaccessil)le nooks of our old 

 Gothic churches, mixed with dust blackened by the anti- 

 quity of six or eight centuries; I also found some in the 

 palaces and crypts in the Thebais, where it perhaps dated 

 from the epoch of the Pharaohs ! 



In our cities it is one of the most abundant corpuscules 

 in the air, the falling snow and the wheeling insect take 

 up an enormous amount as they traverse it. I have 

 counted as many as forty or fifty grains on the wings of 

 certain flies. It also attaches itself to the surface of the 

 body of man and large animals. 



We also discover in the air the skeletons of diff'erent 

 infusoria, and what is still more extraordinary, Ave even 

 find there animalcules perfectly alive. We also frequently 

 meet with the debris of insects, filaments of wool, silk, or 

 cotton, tinged with the most various colours; likewise abun- 

 dant refuse of the soil, and even particles of smoke expelled 

 from our manufactories and household fires. Everything is 

 found here, and with a little practice can be readily recog- 

 nized; and the only thing we do not encounter, or what is 

 at any rate prodigiously rare, is the eggs and seeds with 

 which the panspermists burden it. 



All atmospheric corpuscules penetrate with the air 

 into our respiratory organs. Hence our lungs ahvays con- 

 tain a certain amount of fecula. I have even discovered 

 microscopic crustaceans living in those of a dead man. 



It is known that the bones of birds, instead of being 



