THE BEGINNINGS OF LIFE. 417 



conclusion that oxygen is not always necessary for the 

 initiation of such processes. 



This announcement., made on a former occasion 1 , 

 seems quite to have paralysed the understandings of 

 some of my readers. The effect produced would have 

 been laughable had it not been rather pitiable. Instead 

 of repeating such simple experiments as I have de- 

 scribed with infusions of hay or turnip, and satisfying 

 themselves as to the truth of what had been said, the 

 scientific world and the public generally have been 

 authoritatively told by more than one of them, that such 

 statements are unworthy of attention; and the excel- 

 lence of many meats, which have been preserved for 

 years in airless and hermetically-sealed tins, has been 

 said to afford a practical denial of the truth of my 

 assertions. 



The differences between the two kinds of experiments 

 are, however, sufficiently notable to account for the 

 apparently discordant results. When provisions are 

 preserved, it is in a tin case that is almost filled, and 

 then hermetically sealed, after all air has been expelled 

 by a prolonged ebullition of its fluid contents 2 . What 

 small space there may be at first between the top of the 

 tin and the upper surface of the provisions, is speedily 

 lessened by the insinking of the top, owing to 

 atmospheric pressure. The meats are thus enclosed in 



1 ' Nature,' Nos. 35, 36, 37, 1870. 



2 Very frequently the closed tins are immediately submitted, for half 

 an hour or more, to a much higher temperature even to 258-26oF. 



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