236 SCIENCE PROGRESS. 



setting up the special fermentation. He pointed out, too, 

 that one organism would carry on the process of decomposi- 

 tion to a certain stage, whilst another organism would carry 

 the process a stage farther, so that ultimately the most 

 complex bodies are broken down through the agency of 

 these putrefactive and fermentative organisms into the 

 simplest products, ammonia, carbonic acid and water, the 

 anaerobic organisms doino- one kind of work, the aerobic 

 organisms another. He demonstrated that through their 

 agency all organic matter, whether animal or vegetable, as 

 soon as it loses its power of assimilating— in fact, as soon 

 as it dies and becomes effete — is broken down into sub- 

 stances which may be assimilated by plants, living organisms 

 in this way being enabled to live on the dead material that 

 had been stored up by previous generations of these same 

 living organisms. 



Pasteur's investigations now, for a time, took a practical 

 turn. The vinegar manufacture, upon which Orleans de- 

 pends very largely for its industries, claimed his attention. 

 The old process was tedious, uneconomical, and precarious. 

 Pasteur, working at the subject, found that a pure culture 

 of the Mycoderma aceti has the power of taking up oxygen 

 and of transferring it to the alcohol of wine, through which 

 process such alcohol is turned into vinegar. He therefore 

 advised that a pure culture of the Mycoderma aceti should be 

 sown in a mixture of wine and vinegar, and that this should 

 be kept at a temperature of 20° or 25 C. At the end of a 

 couple of days the Mycoderma covers the whole liquid, and 

 in eight or ten days this is converted into vinegar, the pro- 

 cess commencing immediately the plant begins to grow. 

 If, however, the process is allowed to go on too far the 

 vinegar is still further broken down, and ultimately every 

 trace of acetic acid may disappear, this being the result of 

 the action especially of certain anaerobic organisms which 

 continue the process of breaking down, so that ultimately 

 nothing but a foul or odourless and tasteless fluid may 

 remain, each step appearing to be the result of one of these 

 processes to which reference has already been made. These 

 researches gave a new life to the Orleans' vinegar manu- 



