230 Atmospheric Life Germs. [April, 



of infusions previously heated, have no other origin than 

 the solid particles which are always carried in the air and 

 left deposited constantly upon everything. Could there still 

 remain the least doubt of this in the mind of the reader, it 

 will be dissipated by the experiments I will now describe." 



The experiments consisted in placing in glass flasks the 

 following liquids, all of which are very changeable in con- 

 tact with ordinary air, yeast liquor, sugar solution and 

 yeast liquor, urine, beet-root juice, and infusion of pears; 

 the flasks were then drawn out so as to have a long neck 

 with many bends in all directions. The liquid is boiled for 

 some minutes, while the steam escapes plentifully from the 

 open neck ; the flasks are then left to themselves without 

 being sealed, and, strange to say, though the air enters, the 

 liquid may be preserved for an indefinite period — an in- 

 teresting fact for those who are accustomed to make experi- 

 ments of such a delicate nature as this subject requires. 

 There is no fear of transporting these flasks from place to 

 place, or submitting them to the varying temperature of the 

 seasons ; the liquids show not the slightest alteration in 

 taste or smell ; they are truly specimens of Appert's food- 

 preserving process. In some cases there was a direct 

 oxidation of the matter, a purely chemical process. But it 

 has already been shown how this action of oxygen was 

 always limited when organised productions were developed in 

 liquids. The explanation of these new facts is, that the air 

 on first entering comes in contact with water vapour at th& 

 temperature of ioo° C, and is so rendered harmless ; what 

 follows enters but slowly, and leaves its germs or particles 

 of active matter in the moist curvatures of the tube-neck. 

 After remaining many months in a warm place, the necks 

 of the flasks are cracked off by a file-mark without other 

 disturbance, and in twenty-four hours to thirty-six or forty- 

 eight, fungi and infusoria make their appearance in the 

 usual manner. 



The same experiments can be made with milk, but then 

 the milk must be boiled under pressure ; milk has been kept 

 for months in these open flasks without change at a tem- 

 perature of 25 to 30 C. The production of organisms can 

 always be started in these flasks by briskly shaking the 

 liquid or by sealing during ebullition, and after cooling 

 allowing the air to enter suddenly by breaking the point of 

 the tube. 



Many such flasks, exhibited at the Academy of Sciences, 

 were preserved with their contents unchanged for eighteen 

 months, although extremely prone to decomposition. 



