STUDIES ON FERMENTATION. Ill 



derma aceti, which is generally found along with it, but which 

 propagates with difficulty iu neutral saccharine liquids. 



On the following days films of mycoderma vini had spread 

 over the surface of the liquid in the three flasks. To all appear- 

 ance they were very pure ; and the microscope showed the com- 

 I')lete absence of any mixture of mycoderma aceti, lactic ferment, 

 or other foreign growths.* 



On June 26th we decanted and distilled the liquid in A 

 without finding any trace of alcohol. We shook up the liquids 

 in B and C, with ail due precautions, so as to submerge their 

 films as much as possible, and then we raised the temperature 

 of the flasks to 26° C. or 28° C. (82° F.). For some days after- 

 wards we saw a constant succession of minute bubbles of 

 carbonic acid gas rising through the liquid, which remained 

 bright under the part of the film that had not fallen in. It had 

 all the appearance of a slow but continuous fermentation. 



On June 29th we decanted and distilled the liquid in B, and 

 found in it an appreciable quantity of alcohol, which showed 

 itself in the first distillation. The flask C, which was shaken 

 afresh, continued to give signs of fermentation, but, some days 

 later, the evolution of the bubbles ceased. 



On July 15th, 1873, we examined the flask with its film and 

 its deposit of mijcoderma vini, without finding a trace of any 

 foreign growths, either in the shape of penicilliiim glaucum, or 

 mucor mucedo, or rhi/zopus nigrans, or mijcoderma aceti, or, in 

 short, any of the organisms which could not have failed to 

 appear on the surface of a substratum so peculiarly adapted to 

 their development, had it been in the nature of mycoderma vini 



* It is a very easy matter to study the liquids and growths in our 

 flasks during the course of a single experiment. We take out the glass 

 stopper that closes the india-rubber tube on the straight-neck, and, by 

 means of a long rod or a glass tube previously passed through the 

 flame, take up a quantity, which we draw out immediately for micro- 

 scopical examination. "We then replace the glass stopper, taking care 

 to pass it through the flame before doing so, to burn up any organic 

 particles of dust that it may have picked up from the table on which we 

 laid it. 



