228 Atmospheric Life Germs. [April, 



alkaline from the carbonate of ammonia resulting from the 

 changed urea, a peculiar fungus in necklace-like groups, 

 and this organism Pasteur is fully persuaded is the cause of 

 urea being converted into carbonate of ammonia. An in- 

 teresting observation was made with regard to the turbidity 

 of liquids, which generally is the first sign of alteration ; 

 this is caused not merely by the presence of minute 

 organisms, such as bacteria, but by their movements in the 

 liquid ; for when they are dead they settle to the bottom of 

 the vessel, and the liquid becomes clear again. Many 

 flasks of urine were treated in the manner already described 

 — that is to say, they were boiled, and heated air was 

 admitted to them. After preservation for months at 25 to 

 30° C. without ■ change, plugs of asbestos through which 

 air had been drawn were introduced ; and then in cases 

 where the liquid was alkaline, strings of this peculiar fungus 

 were found invariably, and crystals of ammonio-magnesian 

 phosphate were deposited. It was observed that Bacterium 

 termo appears in a liquid before any other organism. This 

 infusorium is so small that it would be impossible to dis- 

 tinguish its germ ; but even if the appearance of its germ 

 were known it would be still less possible to recognise it 

 among the various particles of organised dust collected from 

 suspension in the atmosphere. 



In experimenting with milk boiled in flasks and exposed 

 to heated air, it was found that generally in from eight to 

 ten days, but in one case after so long a time as a month, 

 the milk was found to be curdled. Microscopic examination 

 showed that the whey was filled with vibriones, often of 

 the species Vibrio lineola, and bacteria. The air of the 

 flasks showed that the oxygen was replaced by carbonic 

 acid ; yet swarms of these vibriones were living in an 

 atmosphere without oxygen. The most important observa- 

 tion which leads to an explanation of the extraordinary 

 behaviour of milk in these experiments, is the facl: that no 

 mucor, torula, or penicillium — nothing but bacleria or 

 vibriones — were found in the liquid. The obvious conclusion 

 is, that these organisms or their germs are not destroyed by 

 a temperature of ioo° C. when the heated liquid which 

 serves to develop them enjoys certain properties. To test 

 this supposition, the milk was boiled under pressure, so 

 that the temperature was raised during ebullition to no°C, 

 and then heated air was admitted, of course at the usual 

 atmospheric pressure ; flasks treated in this way were kept 

 an indefinite period without the production of any life what- 

 ever. The milk preserved its flavour, its odour, and all its 



