954 
which have a definite structure. Nearly 
all of them secrete definite chemical prod- 
ucts capable of producing fermentation. 
The insoluble, or organized ferments, are 
composed mainly of nitrogenous com- 
pounds, but also contain non-nitrogenous 
and mineral matter. Some, as the tuber- 
cular organism, contain cellulose. 
No. 2—Soluble Ferments or Enzymes 
Enzymes are organic compounds, se- 
creted by cells, and have the property of 
producing chemical changes. They are 
also called soluble ferments, chemical 
ferments, and diastases. Diastase is a 
white amorphous compound, converting 
starch by fermentation into dextrine and 
sugar. It is found in the sap of plants, 
and in animal saliva. There are a great 
many kinds of soluble ferments, some of 
which as diastase are capable of acting 
upon carbo-hydrates, while others, as 
pepsin and pancretin, act upon proteid 
bodies. Enzymes produce chemical 
change, without entering into the com- 
position of the substance or giving 
up any of their material to the reacting 
compounds. A small amount of diastase 
will change a large amount of starch 
to soluble forms, without losing its pow- 
er of action. The enzymes are all sol- 
uble in water and are precipitated with 
strong alcohol. Their action is not gen- 
erally retarded by antiseptics and chemi- 
cals which are capable of destroying the 
organized ferments. When seeds are 
soaked in water, the diastase and pro- 
teose enzymes are extracted and if pre- 
Cipitated in alcohol and recovered they 
appear as a light gray powder. An or- 
ganized ferment is a low form of plant, 
while a soluble ferment is a chemical 
compound. 
No. 3—Aerobic and Anerobic Ferments 
Ferments that require oxygen for their 
existence are aerobic while those cap- 
able of working in the absence of oxygen 
are anerobic. The aerobic ferments pro- 
duce carbon dioxide, water, ammonia and 
hydrogen sulfid as final products while 
anerobic ferments usually produce inter- 
mediate products as organic acids. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
No. 4—Conditions Necessary to Fermen- 
tation 
The conditions necessary to fermenta- 
tion are: 
(1) Moisture. 
ture. (3) A ferment body. 
mentable substance. 
Moisture is necessary in order that 
chemical changes may take place. Dur- 
ing fermentation water enters often into 
the chemical reaction, as in hydration 
changes, and is also necessary as a 
medium of exchange for the chemical 
products of the reaction. 
The most favorable temperatures for 
the fermentation are between 15 and 60 
degrees Centigrade. Below zero and 
above the boiling point of water, fer- 
ments are inactive. Some ferments re- 
quire a different temperature for activ- 
ity from any others. 
A ferment body is always necessary to 
start the fermentation change, and in 
the absence of a ferment, either organ- 
ized or unorganized, no ferment can take 
place. 
A fermentable substance, with the right 
kind of ferment to act upon it, is also 
requisite, as a ferment which acts upon 
one class of bodies is incapable of chang- 
ing starch to soluble forms. When a sub- 
stance is freed from all ferments and is 
protected from all sources of outside con- 
tamination, it is in a sterile condition. 
Many forms of fermentation are produc- 
ed by the spores of organized ferments 
gaining access to a material along with 
dust particles carried in the air. In the 
preservation of food, a knowledge of the 
conditions necessary for fermentation is 
made use of. The products formed by 
ferments are numerous, as are ferment 
bodies capable of acting upon all forms 
of organic matter. Some of the ferments 
assist in the digestion of food and in the 
preparation of food products, while others 
take an important part in every-day life 
affairs, and in agriculture in the libera- 
tion of plant food. The growth of plants, 
the preparation of foods, their digestion 
and the manufacture of food products 
all depend largely upon fermentation. 
(2) Favorable tempera- 
(4) A fer- 
