i873-] Atmospheric Life Germs. 229 



properties. Sometimes a slight oxidation of fatty matter 

 took place, as could only be expected in such a considerable 

 body of air ; this was proved by an analysis of the air. 

 In such cases the milk had a slightly suety taste. But 

 what condition prevents the development of vibriones in 

 sugar solutions and urine when heated to ioo° C. ? It is 

 the fact that they contain a trace of acid. Milk is an 

 alkaline liquid. If a liquid of the following composition : — 



Sugar 10 grms. 



Yeast water 100 c.c. 



Carbonate of lime ... 1 grm. 

 be boiled in flasks at ioo° C, filled with heated air and 

 sealed up and left to itself at 25 to 30 , in from two to 

 four days it becomes turbid from vibriones, which have a 

 very lively motion. It was found that a species of mucor 

 after a time covered the surface of the liquid. It seems, 

 therefore, that under these particular conditions, that the 

 germs of this cryptogam had resisted the temperature of 

 boiling water. An important confirmation of these ex- 

 periments regarding the failure of a temperature of ioo° C. 

 to destroy certain germs here follows. Milk which had 

 been preserved some months had a plug of asbestos pre- 

 sumably containing germs introduced into it by the manner 

 already described ; it was sealed up, and the flask was then 

 plunged into boiling water; in eight days bacteria and 

 vibriones were found in swarms. It was further discovered 

 that 108 was too low a temperature to effect the preservation 

 of these liquids. 



It cannot be too forcibly impressed on the reader by what 

 means and with what success Pasteur demonstrated the fact 

 of myriads of organisms occupying comparatively small 

 volumes of air. This is a point to which his detractors 

 have willingly made themselves blind ; they tell us the 

 organisms are few in number without any experimental 

 proof; while, on the other hand, Dr. Angus Smith and 

 Mr. Dancer estimated that there were 37^ millions of 

 organisms, many of which were recognisable, in 2500 litres 

 of Manchester air.* 



A nother Method for showing that all the Organisms produced by 



previously heated Infusions have for their origin the particles 



which exist suspended in ordinary Atmospheric Air. 



Says Pasteur, " I believe it to be rigorously established 



in the preceding chapters that all the organised productions 



* Air and Rain, p. 505. 



