Pasteur on Spontaneous Generation. ci 
Sixty-three flasks were each one-third filled with a clear 
liquid obtained by filtering water mingled with the scum of 
beer, all solid matter being removed by the process of filtering. 
This liquid is known to be very susceptible of change, for expo- 
sure to ordinary air for two or three days is sufficient to give 
birth to small infusoria or a variety of mucedines. The fluid 
was boiled in all the flasks and they were hermetically sealed as 
in the previous experiments. Twenty of the flasks thus pre- 
pared were opened and closed in the country far from any habit- 
ation, at the foot of those heights which form the first plateau of 
of the Jura mountains, 
Twenty other flasks were filled with air upon one of the 
mountains of the Jura 850 metres (2789 ft.) above the level of the 
sea. Another series of twenty flasks were carried to Montanvert 
near the Mer de Glace to an elevation of 2000 metres (6562 ft.) 
oa they were filled with air and hermetically sealed like the 
others, : 
OF the twenty flasks opened in the level country six devel- 
oped organic productions. Among the twenty flasks opened 
upon the plateau of the Jura, only five developed organisms. 
But of the twenty flasks filled with air at Montanvert, when a 
strong wind was blowing from the gorges of the Glacier des 
Bois, one only produced organisms. 
_ These experiments show that the air from elevated localities 
18 remarkably free from those germs which give origin to organic 
products. 
_ In collecting air for these experiments the following precau- 
tions were adopted to avoid as far as possible the intervention of 
dust carried by the operator or deposited on the outside of the 
flask or other implements required in performing the experi- 
ments. ‘The elongated neck of the flask was first heated in the 
flame of a lamp and a scratch was made upon the glass with a 
file. The flask was then raised above the head with the end of 
the neck turned toward the wind and the pont was broken off 
with long iron forceps, the branches of which had previously 
passed through flame to destroy any dust adhering to their sur- 
face so that it might not remain to be driven into the flask by 
the sudden rush of air when the point of the flask was broken. 
Great pains were taken lest the agitation of the liquid in the 
flasks Fusing transit might exert some influence unfavorable to 
the development of infusoria or mucedines. Ang 
The following results are therefore without objection and they 
show the entire difference between the air of the plain or of ele- 
vations and that of inhabited places. Pasteur’s first experiment 
‘at the Glacier des Bois was interrupted by a circumstance which 
had not been foreseen. He had taken to close the points of the 
flasks, after they were filled with air, an eolipile lamp fed with 
