722 THE UNIVERSE. 



filled with marrow, are perfectly hollow, and that by means 

 of a curious mechanism they communicate with the lungs 

 and assist respiration; hence these pneumatic bones are 

 Avell suited for retaining the aerial corpuscules which reach 

 their cavities. A j^eacock bred in a chateau, presented in 

 its bones abundant filaments of wool and silk tinted with 

 the most magnificent colours ; these were clearly remains 

 of the rich dresses of the noble ladies of the place, or of 

 work executed by their delicate hands. On the contrary, 

 in fowls from the humble abode of a baker the pneumatic 

 cavities were almost solely stuflTed with meal and the re- 

 mains of coarse clothes: in those of a charcoal-burner they 

 displayed numerous particles of charcoal. 



In woodpeckers, which inhabit none but the most soli- 

 tary parts of our forests, the respiratory passages contain 

 only the remains of leaves and bark. In contradistinction to 

 this, the bones of the crows, which pass part of their lives 

 on our roofs and part in the fields, are filled with every- 

 thing that circulates in the difterent places which they 

 frequent. We find in them variously coloured filaments 

 of wool and cotton, flour and smoke, which they acquire 

 on the roofs of our dwellings, and lastly fine vegetable par- 

 ticles which they inhale in the midst of the woods. 



It is curious to see the habits of animals told thus by 

 an examination of their respiratory canals. 



But everywhere, whether we examine the air or the 

 innermost organs of animals, we only find a very insignifi- 

 cant quantity of those eggs or seeds with which the pan- 

 spermists nevertheless maintain that the air is loaded. 



