Manchester Memoirs, Vol. lix. (191 5), No. 11. 27 



of wine and beer, by replacing by exact ideas the 

 empiricism which had been up to then the sole guide. 



Pasteur's discoveries have besides given birth to a 

 new industry, the industry of the preserving of food- 

 stuffs. Numerous products, which at one time could only 

 be kept for a few days, have now become articles of 

 commerce and are preserved for months and even for 

 years. It is only necessary to enclose them in boxes or 

 glass jars hermetically sealed in such a way as to protect 

 them from the germs of the minute organisms which 

 bring about their decomposition (fermentation). Let us 

 suppose for a moment that we wish to preserve some 

 milk. We then place the milk to be preserved in a 

 bottle, which we close with a cork. We place the sealed 

 bottle in a kettle containing boiling water. After twenty 

 minutes the bottle is taken out again. The milk has 

 been sterilised (pasteurised), that is to say, the germs of 

 decomposition (fermentation) which it might contain 

 have been killed by the heat ; the cork prevents the 

 entrance of fresh germs, and the milk remains preserved 

 as long as the bottle remains sealed. 



Thus a problem which seemed insoluble is solved by 

 the simplest of means. By this process food-stuffs of all 

 kinds can be preserved, the principle remaining always 

 the same, although the nature of the containing vessels 

 and the details of the operation differ according to the 

 products to be preserved. 



When one thinks for a moment of the innumerable 

 boxes (tins, etc.) and bottles of preserved goods in every 

 grocer's shop, things of daily use, one realises the full 

 importance of Pasteur's discovery. One realises even 

 more its importance when one takes into consideration 

 the enormous quantities of products which one can send 

 to clay from one country to another, and preserve from 



