54 PHYSIOLOGY OF NUTRITION 



received a practical application at the hands of a French cook, Francois Appert, 

 who started a factory for making preserves. He found that it was possible to 

 keep meats, vegetables and liquids unspoiled for unlimited periods of time, if 

 these materials were placed in hermetically sealed jars and then heated in 

 boiling water. Appert published his experiments in a book, which passed 

 through many editions; 1 the book brought him fame, the preserves brought him 

 a fortune. We have here a conspicuous example of the dependence of technical 

 arts upon theoretical knowledge; Spallanzani, in solving the purely philosophical 

 question of the origin of living things on the earth, thereby gave Appert the 

 opportunity to found a new industry. 



Since the objection was raised against Spallanzani's experiment, that the 

 closed vessels contained an inadequate supply of air and that the quality of what 

 air there was must be greatly impaired by the high temperature, Franz Schultze 

 performed the following experiment in 1836. A glass flask (Fig. 31) half full 

 of an organic infusion and tightly closed with a cork stopper, through which 

 two bent glass tubes were passed, was subjected to active boiling for some 



Fig. 31. — Arrangement of bottle and potash bulbs in Schultze's experiment. 



time. While hot steam was still escaping from both tubes he attached a potash 

 bulb to each, one filled with potassium hydroxide solution and the other with 

 sulphuric acid, after which the apparatus was allowed to cool. Twice a day, 

 for three months thereafter, air was drawn through the flask, entering through 

 the sulphuric acid and passing out through the alkali. No organisms of any 

 kind were found in the solution. All the germs present in the entering air were 

 removed by the sulphuric acid. In this experiment the air retained its usual 

 composition and was not heated. 



But this experiment did not seem to be entirely convincing, and it was 

 only by the remarkable investigations of Pasteur that the question of spon- 

 taneous generation was finally and conclusively settled in the negative. Pas- 

 teur (1857) closed glass flasks of various solutions with cotton plugs and sub- 

 jected them to prolonged boiling. If the boiling had been continued sufficiently 



1 Appert, Charles, L'art de conserver pendant plusieurs annees toutes les substances animales et vege- 

 tans. 2nd ed. Paris, 1811. Idem, Le livre de tout les menages ou l'art de conserver pendant plusieurs 

 annees les substances animales et vegetaies. 3rd ed. Paris, 1813. A 5th ed. was published in 1842, or 

 earlier. None of these has been seen in preparing this note; the references are taken from: Catalogue 

 general des livres imprimes de la Bibliotheque Nationale, Paris 3 : 736. 1899. — -Ed. 



