206 THE IXOATING-MATTEE OP THE AIE. 



he even caused the air to bubble through the solution, 

 and finding that though Torula and Penicillium were 

 luxuriantly developed in the liquid, Bacteria never 

 made their appearance, he concluded, ' not merely that 

 the conditions of origin and growth of Bacteria and 

 fungi are considerably different, but that, as regards 

 the former, the germinal matter from which they spring 

 does not exist in ordinary airH'^ 



Dr. Sanderson subsequently reaffirmed the position 

 here laid down. ' In my preceding experiments,' he 

 says, ' it has been shown that, although TontJa-cells and 

 Penicillium appear invariably, and without exception, 

 on all nutritive liquids of which the surfaces are ex- 

 posed to the air, without reference to their mode of 

 preparation, no amount of exposure has any effect in 

 determining the evolution of Bacteria.^ ^ And, again, 

 with reference to another experiment: — 'The result 

 shows that ordinary air is entirely free from living 

 Bacteria.''^ His general conclusion is that, as regards 

 the development of Bacteria in organic liquids, 'water 

 is the contaminating agent.' 



Upon these experiments, and the conclusion drawn 

 from them, an argument has been founded by Dr. 

 Bastian,'' which would be weighty were its basis smre. 

 In reference to the Presidential Address of the British 

 Association in Liverpool,' he argues thus: — 'Speaking 

 of living Bactei'ia-geTnis, Professor Huxley summed 

 up by saying, "considering their lightness, and the 



' Appendix to the Thirteenth Report to the Medical Officer of 

 the Privy Council for 1871, p. 335. 



" 'Appendix,' p. 338. Though Dr. Sanderson speaks of 'all 

 nutritive liquids,' if I understand him aright, he reaUy tried but 

 one, and that vpas a mineral solution, not an animal or vegetable 

 infusion. 



» 'Appendix,' p. 339. • ' Evolution,' p. ii. 



' Brit. Assoc. Report, 1870. 



