2)8 THE BEGINNINGS OF LIFE. 



only reveals what habitats they prefer, and the nature 

 of their food, but even, when they are domestic, the 

 trade or occupation of those amongst whom they have 

 lived.' He found that the long bones of birds living 

 in towns and in the neighbourhood of human habi- 

 tations contained an abundance of particles of carbon, 

 and filaments of the various kinds of textile fabrics, 

 in addition to different sorts of starch particles ^ But 

 the more the animal lived in regions remote from 

 human habitations, the more rare did such material 

 become — so that in those continually dwelling in the 

 midst of forests nothing of this kind was to be met 

 with. The respiratory cavities of such birds, on the 

 contrary, contained an abundance of vegetable debris — 

 of epidermic tissue and particles of chlorophyll. ^ But,' 

 M. Pouchet says 2, ^ in all our observations, which 

 without exaggeration one might reckon by hundreds, 

 we have never encountered either a single spore, a 

 single egg of an Infusorial animalcule, or a single one 

 of these in the encysted condition.' 'And,' he adds, 

 ^ if in all these minute researches we have succeeded 

 in finding starch everywhere, wherever it existed, is it 

 possible that the spores and the atmospheric eggs could 

 alone have escaped us?' If starch particles could pene- 

 trate into such cavities, ova or spores nearly similar in 



^ Valuable additional information on this part of the subject has 

 been furnished by Dr. Sigerson (' Monthly Microscop. Journal,' Aug. 

 1870). 



2 ' Compt. Rend.' torn. 1. p. 11 27, 



