SPONTANEOUS GENERATION. 487 



the same test, yielded the same result. From time to time, moreover, 

 during the last two years, I have placed glass tubes, containing clear 

 infusions of turnip, hay, beef, and mutton, in iron bottles, and sub- 

 jected them to air-pressures varying from ten to twenty-seven atmos- 

 pheres pressures, it is needless to say, far more than sufficient to 

 tear a preserved meat-tin to shreds. After ten days these infusions 

 were taken from their bottles rotten with putrefaction and teeming 

 with life. Thus collapses an hypothesis which had no rational founda- 

 tion, and which could never have seen the light had the slightest at- 

 tempt been made to verify it. 



Our fifty-four vacuous and pellucid flasks also declai-e against this 

 heterogenist. We expose them to a warm Alpine sun by day, and 

 at night we suspend them in a warm kitchen. Four of them have 

 been accidentally broken ; but at the end of a month we find the fifty 

 remaining ones as clear as at the commencement. There is no sign 

 of putrefaction or of life in any of them. We divide these flasks into 

 two groups of twenty-three and twenty-seven respectively (an acci- 

 dent of counting rendered the division uneven). The question now is 

 whether the admission of air can liberate any generative energy in 

 the infusions. Our next experiment will answer this question and 

 something more. We carry the flasks to a hay-loft, and there, with a 

 pair of steel pliers, snip off the sealed ends of the group of twenty- 

 three. Each snipping-off is of course followed by an inrush of air. 

 We now carry our twenty-seven flasks, our pliers, and a spirit-lamp, 

 to a ledge overlooking the Aletsch glacier, about two hundred feet 

 above the hay-loft, from which ledge the mountain falls almost pre- 

 cipitously to the northeast for about a thousand feet. A gentle wind 

 blows towai'd us from the northeast that is, across the crests and 

 snow-fields of the Oberland mountains. We are, therefore, bathed by 

 air which must have been for a good while out of practical contact 

 with either animal or vegetable life. I stand carefully to leeward of 

 the flasks, for no dust or particle from my clothes or body must be 

 blown toward them. An assistant ignites the spirit-lamp, into the 

 flame of which I plunge the pliers, thereby destroying all attached 

 germs or organisms. Then I snip off the sealed end of the flask. 

 Prior to every snipping the same process is gone through, no flask 

 being opened without the previous cleansing of the pliers by the flame. 

 In this way we charge our twenty-seven flasks with clean vivifying 

 mountain-air. 



We place the fifty flasks, with their necks open, over a kitchen- 

 stove, in a temperature varying from 50 to 90 Fahr., and in three 

 days find twenty-one out of the twenty-three flasks opened on the 

 hay-loft invaded by organisms two only of the group remaining free 

 from them. After three weeks' exposure to precisely the same condi- 

 tions, not one of the twenty-seven flasks opened in free air had given 

 way. No germ from the kitchen-air had ascended the narrow necks, 



