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these several maladies of wine were described and figured by 

 Pasteur, it must not be supposed that the mechanism of these pro- 

 cesses was investigated with anything like the completeness of the 

 acetifi cation process. A large amount of work still remains to be 

 done in connexion with these more obscure difficulties which attend 

 the production of soured wine, but to Pasteur is due the broad 

 explanation of these phenomena as dependent upon the presence of 

 foreign organisms, and the further elucidation of the subject is 

 chiefly a matter of laborious detail. 



Pasteur, however, did not rest content with having discovered 

 the cause of the deterioration of wine ; he at once set to work to 

 find out a means for its prevention, and in the first instance he 

 sought to suppress the mischievous vitality of the micro-organisms 

 present in wine by the addition of antiseptics. These experiments 

 were not, however, satisfactory, and he, therefore, had recourse to 

 heating the wine, and in this manner effecting the destruction of, or 

 ensuring the paralysis of, the micro-organisms which produced the 

 undesirable changes in its quality. This heating or partial sterilisa- 

 tion of a liquid — for the temperature employed was far below boiling, 

 and was only designed to paralyse the activity of the micro- 

 organisms present and not necessarily to destroy them — was first 

 applied by Pasteur, and is now generally known as " pasteurisation." 

 Ic has of late been largely and successfully employed in connexion 

 with wine, beer, milk, cream, and other food materials of a perishable 

 nature. 



Pasteur's fermentation studies were, however, interrupted by an 

 incidental investigation into which he was, so to speak, forced by his 

 superiors, but which proved an admirable preparatory school for 

 those great labours on micro-organisms and disease which have 

 rendered his name a household word throughout the civilised 

 world. 



In 1865 the silkworm culture, which forms such an important 

 industry in the south of France, was threatened with ruin in conse- 

 quence of a most disastrous disease having made its appearance 

 amongst the worms. A commission of inquiry was appointed, of 

 which Dumas was made chairman, and he at once turned to Pasteur 

 for assistance, requesting him to undertake the scientific investiga- 

 tion of the scourge which had wrought such misery amongst silk- 

 worm proprietors, reducing a successful and wealthy industry to the 

 verge of destruction. Pasteur was very loath to leave his researches 

 on fermentation and urged his entire ignorance of the subject, but 

 Dumas would not listen to any plea as to his incapacity to undertake 

 the work. " Tant mieux," he replied to Pasteur, "vous n'aurez 

 d'idees que celles qui vous viendront de vos propres observations." 



During five years Pasteur was unceasingly engaged in studying 



