THE BEGINNINGS OF LIFE. 293 



water, or the substance infused? or have they been 

 produced de novo, and without the agency of germs ? 

 These are the questions which most urgently press for 

 solution. Can Archebiosis still take place, or does all 

 Life proceed from pre-existing Life ? 



I think it will be at once recognised, that it 

 would be altogether useless to search in the air for the 

 germs of plastide-particles, or of Bacteria. Even M. 

 Pasteur himself admits this. Speaking of the germs of 

 the Bacterium^ c which shows itself in all sorts of in- 

 fusions, and which almost always appears before the 

 other Infusoria,' he says (Annal. de Chimie et de 

 Physique, 1862, p. 56): c This Infusorium is so small, 

 that ont could not distinguish its germ, and still less 

 affirm the, presence of such germ, if it were known, 

 amongst the organised corpuscles belonging to the dust 

 in suspension in the atmosphere.' 



No investigations as to what the air does or does not 

 contain can, therefore, throw much direct light upon this 

 question as to the mode of origin of Bacteria. Seeing 

 that the champion of the Panspermatists admits this, 

 we may for the present completely disregard this aspect 

 of the question, merely pointing out that probably more 

 than nine-tenths of the discussion and experimentation 

 which has taken place upon the question of the exist- 

 ence or non-existence of c germs ' in the air has been 

 almost wholly irrelevant, and without value for the 

 settlement of the main question at issue (see p. 297). 



We must, then, have recourse to a microscopical 



