24 ORIGIN OF LOWEST ORGANISMS. 



and structure declare them to be organized." Some 

 of these, he thinks, resemble the spores of fungi, and 

 others the ova of ciliated infusoria, though he adds : 

 " But as to affirming that this is a spore, much less the 

 spore of any definite species, and that one is an 

 egg, and belonging to such an infusorium, I believe 

 that this is not possible." He limits himself, in fact, 

 to the statements, that the corpuscles which he found, 

 were (in his opinion) evidently organized ; that they 

 resembled in form and appearance the germs of the 

 lower kinds of organisms ; and that, from their 

 variety in size, they probably belonged to many 

 different sorts of living things. Even here, therefore, 

 we have to do with the impressions of M. Pasteur, 

 rather than with verified statements. All that has 

 been established by his direct investigation as to the 

 nature of the solid bodies contained in the atmosphere 

 is this : that the air contains a number of round or 

 ovoidal corpuscles, often quite structureless, which 

 he could not distinguish from the spores of fungi * 

 some of which, being about the right size, were round 

 or ovoidal, and structureless. In addition, however, 

 it has been shown that the air contains other rounded 

 corpuscles which are similarly structureless, though 

 composed of silica or starch. It may therefore be 

 asked, in the first place, whether the conclusion is 



* Those which he believed to be eggs of ciliated infusoria, 

 may be at once dismissed from consideration, as we are not at 

 present concerned with the origin of organisms of this kind. 



