150 THE LIFE OF PASTEUR 



that this law of dissolution and return to a gaseous state is 

 accomplished." 



Coming back to his special subject, he pointed out to vinegar 

 manufacturers the cause of certain failures and the danger of 

 certain errors. 



It was imagined for instance that some microscopic beings, 

 anguillulae, of which Pasteur projected an enlarged wriggling 

 image on the screen, and which were to be found in the tubs of 

 some Orleans vinegar works, were of some practical utility. 

 Pasteur explained their injurious character : as they require air 

 to live, and as the mycoderma, in order to accomplish its work, 

 is equally dependent on oxygen, a struggle takes place between 

 the anguillulae and the mycoderma. If acetification is success- 

 ful, if the mycoderma spreads and invades everything, the 

 vanquished anguillulae are obliged to take refuge against the 

 sides of the barrel, from which their little living army watches 

 the least accidental break of the veil. Pasteur, armed with a 

 magnifying glass, had many times witnessed the struggle for 

 life which takes place between the little fungi and the tiny 

 animals, each fighting for the surface of the liquid. Some- 

 times, gathering themselves into masses, the anguillulae suc- 

 ceed in sinking a fragment of the mycodermic veil and victori- 

 ously destroying the action of the drowned plants. 



Pasteur related all this in a vivid manner, evidently happy 

 that his long and delicate laboratory researches should now 

 pass into the domain of industry. He had been pleased to find 

 that some Orleans wine merchants heated wine according to 

 his advice in order to preserve it ; and he now informed them 

 that the temperature of 55° C. which killed germs and vegeta- 

 tions in wine could be applied with equal success to vinegar 

 after it was produced. The active germs of the mycoderma 

 aceti were thus arrested at the right moment, the anguillulae 

 were killed and the vinegar remained pure and unaltered. 

 "Nothing," concluded Pasteur, "is more agreeable to a man 

 who has made science his career than to increase the number 

 of discoveries, but his cup of joy is full when the result of his 

 observations is put to immediate practical use." 



This year 1867 marks a specially interesting period in 

 Pasteur's life. At Alais he had shown himself an incomparable 

 observer, solely preoccupied with the silkworm disease, think- 

 ing, speaking of nothing else. He would rise long before any 

 one else so as to begin earlier the study of the experiments he 



