VITALITY OF PUTEEFACTIVE OEGANISMS. 147 



This result is in perfect harmony with all the results 

 of last year. Chamber after chamber was then charged 

 with infusions of hay, which were afterwards subjected 

 to the boiling temperature for five minutes. In every 

 chamber the infusion remained perfectly clear mitil 

 purposely infected from without. There was no instance 

 observed last year in which five minutes' boiling failed 

 to sterilize hay-infusion, whether neutralized or un- 

 neutraUzed. 



Thus, on the 26th of November, 1875, a group of 

 three test-tubes was charged with hay-infusion of the 

 same specific gravity and of the same degree of alkalinity 

 as that found most resistant by Dr. Roberts. They were 

 protected by glass shades, the air within the shade being 

 calcined by an incandescent platinum wire in the man- 

 ner described in the last essay.' The tubes were boiled 

 for five minutes, the subsequent intrusion of contami- 

 nated air being prevented by a ring of cotton-wool. 

 Thirteen months afterwards the infusion, greatly con- 

 centrated by evaporation, exhibited its pristine deep 

 transparency. A second similar group of tubes was 

 charged with alkalized hay-infusion on the 27th of last 

 January, and on the 5th of December (that is to say, 

 after a period of more than ten months) the infusion 

 was found perfectly clear. 



A number of hermetically-sealed tubes charged with 

 the same infusion, and boiled for only three minutes, 

 have maintained for more than a year both their primi- 

 tive transparency and their water-hammer sound. Thus 

 many of the earliest experiments of the present year, 

 and the whole body of last year's experiments, are in 

 complete harmony with each other. 



This harmony was, however, disturbed by some of 

 the foregoing experiments with bulbs and tubes, and it 

 ' Phil. Trans., vol. clxvi. p. 50. 



