802 FRAGMENTS OF SCIENCE 



its proper antecedent. Thus, before fermentation could 

 be understood, the microscope had to be invented, and 

 brought to a considerable degree of perfection. Note the 

 growth of knowledge. Leeuwenhoek, in 1680, found yeast 

 to be a mass of floating globules, but he had no notion 

 that the globules were alive. This was proved in 1835 by 

 Cagniard de la Tour and Schwann. Then came the ques- 

 tion as to the origin of such microscopic organisms, and 

 in this connection the memoir of Pasteur, published in 

 the *'Annales de Chimie" for 1862, is the inauguration of 

 a new epoch. 



On that investigation all Pasteur's subsequent labors 

 were based. Ravages had over and over again occurred 

 among French wines. There was no guarantee that they 

 would not become acid or bitter, particularly when ex- 

 ported. The commerce in wines was thus restricted, and 

 disastrous losses were often inflicted on the wine-grower. 

 Every one of these diseases was traced to the life of an 

 organism. Pasteur ascertained the temperature which 

 killed these ferments of disease, proving it to be so low 

 as to be perfectly harmless to the wine. By the simple 

 expedient of heating the wine to a temperature of fifty 

 degrees Centigrade, he rendered it unalterable, and thus 

 saved his country the loss of millions. He then went on 

 to vinegar — vin aigre^ acid wine — which he proved to be 

 produced by a fermentation set up by a little fungus called 

 Mycoderma aceti. Torula, in fact, converts the grape juice 

 into alcohol, and Mycoderma aceti converts the alcohol 

 into vinegar. Here also frequent failures occurred, and 

 severe losses were sustained. Through the operation of 

 unknown causes, the vinegar often became unfit for use., 

 sometimes indeed falling into utter putridity. It had been 



