ORIGIN OF LOWEST ORGANISMS, 65 



others, however, who say that organisms are capable 

 of arising de novo, and that fermentation can be 

 initiated without the agency of living things, the 

 above facts appear quite natural. The more complex 

 the nitrogenous or protein materials contained in a 

 solution, the more is it fitted to undergo fermenta- 

 tive changes, which may be accompanied by the de 

 novo origination of living things. Therefore the above 

 results are just as compatible with the notions of 

 M. Liebig and his school, as they are antagonistic 

 to those of M. Pasteur. Certain fluids, it is found, do 

 not undergo change ; whilst other fluids, of a more 

 complex description, will ferment under the influence 

 of similar conditions. Prolonged ebullition also, by 

 breaking up some of the more unstable compounds 

 of a solution (those which most easily initiate these 

 changes) will retard or prevent its fermentation. 



The complete untenability of M. Pasteur's explana- 

 tions are, however, best revealed by having recourse to 

 a series of comparative experiments, in which portions 

 of the same fluid are boiled for an equal length of time 

 in vessels of different kinds, and are then subsequently 

 submitted, in a water-bath, to the influence of the 

 same temperature. 



I have made many experiments of this kind with 

 different solutions, some of which I will now record. 

 Owing to the different behaviour of the same fluids 

 under different conditions, we are enabled to draw 

 some most important conclusions ; and owing to the 



F 



