OPERATIONS IN A VINEGAR FACTORY. 101 



for the nourishment of the mold ferment, though in a less degree 

 than young wine, and besides living yeast contains alcoholic 

 ferment. 



By heating wine or beer only for a moment to about 158 F., 

 a large portion of the albuminous substances in solution becomes 

 insoluble, and on cooling separates as a flaky precipitate, all fer- 

 ments present in the fluid being at the same time destroyed. 

 Hence for the preparation of a fluid especially adapted for the 

 cultivation of pure vinegar ferment, it is recommended quickly to 

 heat to the boiling point 1 quart of ordinary white wine in a 

 covered porcelain vessel, and, after cooling to the ordinary tem- 

 perature, to mix it with 2 quarts of vinegar. To remove the 

 separated insoluble albuminous substances it is filtered through 

 blotting paper. 



To prepare a nourishing fluid from beer, heat 1 quart to the 

 boiling point, mix it after cooling with 3 quarts of vinegar, add 

 ^ quart of 90 per cent, alcohol, and filter. 



Distribute this fluid in a number of shallow porcelain vessels 

 and place the latter near a window in the heated workroom. To 

 prevent dust from falling into the fluid cover each dish with a 

 glass plate resting upon two small wooden sticks placed across 

 the dish. In two or three days, and sometimes in 24 hours, the 

 commencement of the development of the vinegar ferment will 

 be recognized by the stronger odor of vinegar than that possessed 

 by the original fluid and by the appearance of the surface of 

 the liquid. By observing the latter at a very acute angle, dull 

 patches resembling grease stains and consisting of a large number 

 of individuals of the vinegar ferment will be seen. In a few 

 hours these patches have increased considerably, until finally the 

 entire surface appears covered by a very delicate veil-like layer 

 of vinegar ferment. 



By touching the surface with the point of a glass rod a certain 

 amount of the coating adheres to it, and by rinsing it off in a fluid 

 of similar composition not yet inoculated the ferment quickly de- 

 velops upon it. By placing a drop of the fluid under the micro- 

 scope a picture similar to that shown in Fig. 2, p. 29, presents 

 itself: the entire field of vision is covered with germs of vinegar 

 ferment. 



