96 ORIGIN OF LOWEST ORGANISMS. 



of the observatory, or else with some from the peaks 

 of the Jura,* far away from the haunts of men, had 

 no bearing upon the distribution of germs which was 

 not equally applicable to that of dead organic 

 particles. Such evidence, therefore, was valueless for 

 settling between the rival doctrines of fermentation it 

 could not possibly help us to decide whether living or 

 dead ferments were necessary. Dead organic particles 

 would sink in still air in the same manner as living 

 organisms ;t and similarly, dead organic particles, 

 have been shown to be less and less numerous in the 

 atmosphere in proportion to the elevation obtained. { 

 In these latter experiments M. Pasteur made use of 

 yeast-water (alone or sweetened), and of urine all 

 three of them fluids, which, after having been boiled, 

 are apt to possess only the second degree of fermen- 

 tability. Shortly afterwards, M. Pouchet, in concert 

 with MM. Joly and Musset, repeated these experi- 

 ments, with the sole difference that they employed 

 strong infusions of hay which experiment has shown 

 almost invariably to possess the first degree of ferment- 

 ability. And seeing that all their flasks, after a time, 

 yielded organisms from whatever mountain elevation 



* Loc. cit. pp. 83 and 84. 



t The subsidence of the atmospheric particles has been ably 

 demonstrated by Professor Tyndall. See ' Nature,' 1870. 



% See M. Pouchet's ' Nouvelles Experiences surla Generation 

 Spontanee,' &c., p. 69. 



See various communications in ' Compt. Rend.' (1863), 

 t. LVII. 



