lii 



point out to these manufacturers that instead of waiting the cus- 

 tomary two or three months for the completion of the process, the 

 vinegar could be elaborated in from eight to ten days by simply 

 exposing the vats containing the mixture of wine and vinegar to a 

 temperature of from 20 to 25° C, and sowing on the surface a small 

 quantity of this organism. As in the case of the alcoholic fermenta- 

 tion, so in that of the vinegar or acetic fermentation, Pasteur was 

 neither the first to discover the process, nor the first to see the living 

 ferment, nor yet even the first to connect the process with the life of 

 the micro-organism. The chemical change involved and the part 

 played by oxygen in the souring of wine were already indicated by 

 Lavoisier ; the process was ascribed to catalysis, or contact action by 

 Berzelius in 1829. The familiar skin which forms on the surface of 

 the acetifying liquid was already named mycoderma by Persoon in 

 1822, and the bacterial cells of which this pellicle is composed were 

 seen and actually described under the name of Ulvina aceti by 

 Kiitzing in 1837, who even suspected a connexion between the life of 

 the organisms and the vinegar process. 



But it is here that Pasteur stands out in such bold relief from so 

 many other distinguished savants of the century, for by building up 

 his discoveries on a solid rock of scientific experiment they have with- 

 stood those " whips and scorns of time " which have often succeeded 

 in demolishing the less successfully raised structures of his pre- 

 decessors. 



In perusing the terse summaries in which Pasteur records his 

 labours on the acetic fermentation in the ' Oomptes Bendus,' the 

 breadth and scope of the view which he takes of the phenomena 

 before him at once impress the reader, whilst the alertness of his 

 mind to developments, which even now are only partially realised, is 

 not less remarkable. 



In placing the vinegar process on a sound scientific basis, Pasteur 

 had obviously already broached the subject of the "maladies des 

 vins," for that the souring of wine is one of the most wide-spread 

 ills to which it is subject, is surely well known to all possessing even 

 the most modest of cellars. What more natural, therefore, than 

 that Pasteur should conceive that those other and more mysterious 

 deteriorations which wines so frequently undergo, might receive a 

 rational explanation by the application of the same methods which 

 had elucidated the vinegar process ? Nor were these methods found 

 wanting in dealing with the diseases of wine, for whilst in healthy 

 or normal wines Pasteur found only yeast cells, in all those wines 

 which connoisseurs condemned as diseased he found other micro- 

 organisms as well, and the nature of these micro-organisms was 

 found to vary according to the complaint with which the wine was 

 charged. Although a number of different bacteria connected with 



