310 FRAGMENTS OF SCIENCE. 



fourth series of experiments, in which,- previous to forcing 

 in the air, he permitted the flasks to cool. Into four bottles 

 thus treated he forced prepared air, and after a time found 

 fungi in all of them. What is his conclusion ? Not that 

 the boiling hot liquid employed in his first experiments had 

 destroyed such germs as had run the gantlet of his ap- 

 paratus ; but that air which, previous to being sealed up, 

 had been exposed to a temperature of 212 is too rare to 

 support life. This conclusion is so remarkable that it ought 

 to be stated in Dr. Bennett's own words : " It may be 

 easily conceived that air subjected to a boiling temperature 

 is so expanded as scarcely to merit the name of air, and 

 that it is more or less unfit for the purpose of sustaining 

 animal or vegetable life," 



Now numerical data are attainable here, and, as a 

 matter of fact, I live and flourish for a considerable portion 

 of each year in air of less density than that which Dr. 

 Bennett describes as scarcely meriting the name of air; 

 the Swiss men, women, children, flocks, herds, tadpoles, 

 grasshoppers, flowers, and grasses, do the same, while the 

 chamois rears its kids in air rarer still. 



In a fifth series of experiments sixteen bottles were 

 filled with infusions. Into four of them, while cold, or- 

 dinary unheated and unsifted air was pumped. In these 

 four bottles fungi were developed. Into four other bottles, 

 containing a boiling infusion, ordinary air was also pumped 

 - no fungi were here developed. Into four other bottles 

 containing an effusion which had been boiled and permitted 

 to cool, sifted air was pumped no fungi were developed. 

 Finally, into four bottles containing a boiling infusion, 

 sifted air was pumped no fungi were developed. Only, 

 therefore, in the four cases where the infusions were cold 

 infusions, and the air ordinary air, did fungi appear. 



Dr. Bennett does not draw from these experiments the 

 conclusion to which they so obviously point. On them, on 



