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taneous generation. The real interest of that work for me lies 

 in the connection of this subject with that of ferments which 

 I shall take up again November." 



Pasteur started for Arbois, taking with him seventy-three 

 flasks ; he opened twenty of them not very far from his father's 

 tannery, on the road to Dole, along an old road, now a path 

 which leads to the mount of the Bergere. The vine labourers 

 who passed him wondered what this holiday tourist could be 

 doing with all those little phials ; no one suspected that he was 

 penetrating one of nature's greatest secrets. ' What would 

 you have?" merrily said his old friend, Jules Vercel; "it 

 amuses him!" Of those twenty vessels, opened some dis- 

 tance away from any dwelling, eight yielded organized bodies. 



Pasteur went on to Salins and climbed Mount Poupet, 850 

 metres above the sea-level. Out of twenty vessels opened, only 

 five were altered. Pasteur would have liked to charter a 

 balloon in order to prove that the higher you go the fewer 

 germs you find, and that certain zones absolutely pure contain 

 none at all. It was easier to go into the Alps. 



He arrived at Chamonix on September 20, and engaged a 

 guide to make the ascent of the Montanvert. The very next 

 morning this novel sort of expedition started. A mule carried 

 the case of thirty -three vessels, followed very closely by Pasteur, 

 who watched over the precious burden and walked alongside 

 of precipices supporting the case with one hand so that it 

 should not be shaken. 



When the first experiments were started an incident occurred. 

 Pasteur has himself related this fact in his report to the 

 Acad&nie. " In order to close again the point of the flasks 

 after taking in the air, I had taken with me an eolipyle spirit- 

 lamp. The dazzling whiteness of the ice in the sunlight was 

 such that it was impossible to distinguish the jet of burning 

 alcohol, and as moreover that was slightly moved by the wind, 

 it never remained on the broken glass long enough to her- 

 metically seal my vessel. All the means I might have em- 

 ployed to make the flame visible and consequently directable 

 would inevitably have given rise to causes of error by spreading 

 strange dusts into the air. I was therefore obliged to bring 

 back to the little inn of Montanvert, unsealed, the flasks which 

 I had opened on the glacier." 



The inn was a sort of hut, letting in wind and rain. The 

 thirteen open vessels were exposed to all the dusts in the room 



H 



