102 LOUIS PASTEUR. 



to a very small diameter, at the same time bending 

 the soft glass to and fro, so as to form a sinuous tube. 

 The extremity of this narrow tube remained open. 

 He then boiled his liquid for some minutes until the 

 vapour of the water came out in abundance through 

 the narrow open tube. In these conditions the liquid 

 in the bulb, however putrescible, is preserved indefi- 

 nitely without the least alteration. One may handle 

 it, transport it from place to place, expose it to every 

 variety of climate, place it in a stove with a tempera- 

 ture of thirty or forty degrees, the liquid remains as 

 clear as it was at first. A slight oxidation of the 

 constituents of the liquid, is barely perceptible. In 

 this experiment the ordinary air, entering suddenly 

 at the first moment, finds in the bulb a liquid very 

 near the boiling temperature; and when the liquid 

 is so far cooled that it can no longer destroy the 

 vitality of the germs, the entrance of the air is cor- 

 respondingly retarded, so that the germs capable of 

 acting upon the liquid, and of producing in it living 

 organisms, are deposited in the bends of the still 

 moist tube, not coming into contact with the liquid 

 at all. 



If, after remaining for weeks, months, or even 

 years, in a heated chamber, the sinuous neck of the 

 bulb is snipped off by a file in the vertical part of the 

 stem, after twenty-four or forty-eight hours there 

 begin to appear mildew, mucors, bacteria, infusoria, 



