THE QUESTION OF SPONTANEOUS GENERATION. 107 



would escape alteration. They must not, however, he 

 opened in a room after dusting the furniture or sweep- 

 ing the floor, for in this case all the bulbs would become 

 altered because of the great quantity of germs raised 

 by the dusting and remaining suspended in the air. 



Pasteur started for Arbois with a series of bulbs. 

 Some he opened in the country far from all habitations ; 

 others he opened at the foot of the mountains which 

 form the first range of the Jura ; a series of twenty- 

 four bulbs was opened upon Mount Poupet, at 850 

 meters above the level of the sea ; and, lastly, twenty 

 others were transported to the Montanvert, near the 

 Mer de Glace, at an elevation of 2,000 meters. He 

 afterwards brought his whole collection back to Paris, 

 and in the month of November, 1860, deposited them 

 on the table at the Academy of Sciences. 



Of the twenty bulbs first opened in the country, 

 eight contained organised productions. Of the twenty 

 opened on the heights of the Jura, five only were 

 altered, and of the twenty opened upon the Montan- 

 vert during a strong wind which blew from the 

 glacier, one alone was altered. 



If a similar series of experiments were made in a 

 balloon, it would be found that the air of the higher 

 atmosphere is absolutely free from germs. Care 

 would, however, be necessary to prevent the introduc- 

 tion of dust particles, which the rigging and the 

 aeronauts themselves might carry with them. 



