490 STATE HORTICULTURAL SOCIETY. 



H f , O (alcohol), plus 2 C 0> (carbonic acid gas). Second, the alcohol taking up oxygen 

 from the air forms acetic acid and water. The formula is Ca H 6 O (alcohol) plus 0_, 

 (oxygen) equals C 2 H 4 2 (acetic acid) plus H 2 O (water). Cj 2 H 22 O n , cane sugar. 



The first of these reactions is caused by alcoholic, the second by acetic, fermentation. 

 The determining cause of the first of these reactions will now claim our attention. 



Alcoholic fermentation is only a particular instance of a chemical phenomenon of 

 which living organisms are the cause. A living cell of beer-yeast possesses the property 

 of resolving into alcohol and carbon dioxide, the altered sugar which penetrates through 

 its membraneous envelope. If we substitute for the cell of beer-yeast a cell of lactic 

 ferment, we still see the sugar disappear, but instead of alcohol and carbon dioxide we 

 have lactic acid produced. Says Schutzenbkrger: "The transformation of sugar into 

 alcohol and carbon dioxide, and the conversion of the same body into lactic acid, are 

 chemical phenomena which we can not yet produce by the intervention of heat alone, 

 nor by the additional agency of light or electricity. The force capable of attacking in 

 a certain determinate direction the complete edifice we call sugar, an edifice composed 

 of atoms of carbon, hydrogen, and oxygen grouped according to a determinate 

 law, that force which is manifest only in the living cell of the ferment, is a force as- 

 material as all of those we are accustomed to utilize." 



Beer-yeast when examined under the microscope is seen to be formed of very small 

 spherical or ovoid globules. They are capable of reproducing themselves by means of 

 buds or seminulee, and belong to the vegetable kingdom. It is now very generally 

 admitted that ferments are fungi. 



Pasteur, who has watched these cells multiply, states that in two hours he has seen 

 two cells furnish eight, including the two mother-cells. 



There resides in the organic living cell a force capable of breaking up the complex 

 molecule presented to it as food. It makes no difference whether that cell is a part of 

 a more complex structure, like a tree, or whether it is isolated like that of yeast. 



The second portion of the reaction, by which the alcohol, by taking up oxygen from 

 the air, changes into acetic acid and water, will next claim our attention. In this, or 

 acetic, fermentation, we find not only the fermentable matter and the ferment entering 

 into the reaction, but also that the oxygen of the air becomes a necessary body. In 

 other words, acetic fermentation is a combustion set up by living organisms, which serve 

 as a media between the oxygen of the air and the fermentable body. It has long been 

 known that alcohol contained in fermented liquids, such as wine, beer, etc., will disap- 

 pear under certain circumstances and give rise to vinegar or acetic acid, and that the 

 air, or rather its oxygen, plays an important part in the reaction. It was upon this idea 

 that the process of rapid acetification, called the German process, was founded. In 

 this process, use is made of a large oak vat from six to ten feet in height by three or 

 four in diameter, furnished with a false bottom pierced with holes and placed about 

 twelve inches from the bottom. Some inches higher, the circumference of the vat is 

 regularly pierced with a series of holes passing entirely around it. These openings are 

 inclined from without inward, so as to prevent the escape of the liquid. At the upper 

 part another false bottom is placed, pierced with many small holes. The whole vat is 

 closed by a cover furnished with a funnel, which can be closed. The space between the 

 two false bottoms is filled with beech shavings. All being thus arranged, hot vinegar 

 is poured into the vat. This filters through the shavings and serves to facilitate or set 

 up the oxidation of the alcohol. All of this was done with the idea that the liquid 

 should present as great a surface as possible to the action of the air. But, according to 

 Pasteur, the beech shavings act, not on account of their porosity, but because their 

 surface becomes covered with a thin pellicle of micoderma aceti. 



The many points of contact facilitates the action but is not the determining cause. 

 To prove this, M. Pasteur caused some alcohol diluted with water to trickle down a 

 cord. The drops which fell from the cord, at the end of a month, did not contain the 

 smallest quantity of acetic acid. If we repeat the experiment, after having drawn the 

 cord through a liquid on the surface of which there is a film of micoderma, the alcohol 

 which passes slowly down the cord will be changed to acetic acid. 



If we allow any species of micoderma to develop itself on any organic liquid contain- 

 ing phosphates and nitrogenous organic matter, until the whole surface is covered, and 

 then, by means of a syphon, draw off the nutritive liquid and replace it with an equal 

 volume of water containing ten per cent, alcohol; the plant, placed under these abnor- 

 mal conditions, will immediately set up a reaction between the oxygen of the air and 

 the alcohol of the liquid. The acetification at first is very rapid, but after a time the 

 reaction becomes retarded by the great acidity of the liquid. Its vigor can be renewed, 

 however, by the addition of more alcohol and water. A time, however, comes, says 

 Pasteur, when the plant, becoming partly decomposed, itself communicates to the 

 liquid, in consequence of the organic and mineral matter of its tissues, properties which 

 serve as nutriment for the various species of micoderma. 



