THE USE OF BACTERIA IN THE ARTS. 65 



access. Inasmuch as all organic decomposition 

 is produced by bacterial growth, such sterilized 

 and sealed material will be preserved indefinitely 

 when the operation is performed carefully enough. 

 The methods of accomplishing this with sufficient 

 care are somewhat varied in different industries, 

 but they are all fundamentally the same. It is 

 an interesting fact that this method of preserving 

 meats was devised in the last century, before the 

 relation of micro-organisms to fermentation and 

 putrefaction was really suspected. For a long 

 time it had been in practical use while scientists 

 were still disputing whether putrefaction could be 

 avoided by preventing the access of bacteria. The 

 industry has, however, developed wonderfully 

 within the last few years, since the principles 

 underlying it have been understood. This un- 

 derstanding has led to better methods of destroy- 

 ing bacterial life and to proper sealing, and these 

 have of course led to greater success in the pres- 

 ervation, until to-day the canning industries are 

 among those which involve capital reckoned in 

 the millions. 



Occasionally bacteria are of some value in 

 food products. The gamy flavour of meats is 

 nothing more than incipient decomposition. 

 Sauer Kraut is a food mass intentionally allowed 

 to ferment and sour. The value of bacteria in 

 producing butter and cheese flavours is noticed 

 elsewhere. But commonly our aim must be to 

 prevent the growth of bacteria in foods. Foods 

 must be dried or cooked or kept on ice, or some 

 other means adopted for preventing bacterial 

 growth in them. It is their presence that forces 

 us to keep our ice box, thus founding the ice 

 business, as well as that of the manufacture of 



