4 



FERMENTATION. 



( Reprinted from the Victoria Quarterly.) 



Having just read a small bo>k, " Ferments et Fermentations" by M. Leon Gamier, a countryman 

 of the famous Pasteur, it occurred to me that if I put down a few notes and reflections on the subject, 

 they might perhap- interest leaders of the Victoria Quarterly Magazine. 



Thj word Fermentation fa derived from a Latin word feroere to boil, and originally was given to 

 any phenomenon in which the mass swelled up, giving off bubbles. Familiar examples of this original 

 meaning of the word are to be seen in the working of yeast in dough, and in the manufacture of rum, 

 wine or b er. But the term has become generalised, as it has been discovered that other phenomena 

 such as the souring of milk, and putrefaction, are really due to similar causes, and that the swelling and 

 effervescence are only accidental concomitants. 



We will try then to discover what similarity underlies such apparently totally different processes as 

 the making of rum, and the decay of auimal or vegetable refuse in our streets. 



In order to do so, it will be necessary first to consider what happens in the life of any common 

 plant, such as corn. Let us take a few seeds, and suspend them over water. They soon germinate, 

 forming a few roots and leaves, and then die. These seeds have only moisture of pure water, and air, 

 and yet they have grown. Whence comes their food? By carefully examining the seed in all stages, 

 we find that the greater part of it consists of grains of starch, and that these disappear as the germina- 

 tion and growth of the seed progresses, being changed into sugar; finally, that not only the starch 

 but the sugar also disappears. The starch was the supply of food laid up for the young plant to be 

 used until it could obtain food for itself. But though starch is a convenient form in which to store 

 nutriment for living beings, neither animal nor plant can make use of it in the form of starch. And 

 again the solid grains cannot pass from the closed cells in which they are formed to the cells in which 

 growth is going on, and where food is required. When we eat bread or yams, the starch is changed 

 into sugar by means of a chemical change induced by a secretion in the saliva and pancreatic juice, and 

 it is a similar secretion in seeds which enables the young plant to feed on the stored starch. 



Advantage is taken of this singular property in seed9 in the process of changing barley into malt. 

 Barley to be malted is first steeped and absorbs so much water that it increases about one-fifth in bulk, 

 and one half in weight. Very shortly after the grain has been put into steep, it is found that a sub- 

 stance to w hich the name of diastase has been given, is now formed in the seed. Diastase can be 

 extracted in an impure form from malt, and is so powerful in its action that a certain quantity will 

 change 2,U00 times as much starch into sugar. It is often used in case of bad digestion under the 

 name of " malt extract." When the diastase has done its work, the seedsis dried, germination ceases 

 and the mail is no»v ready for the brewer. The action of diastase involves a chemical re-action in which 

 starch is changed into sugar under its influence, but the diastase does not contribute any of its sub- 

 stance to the products of the re-action, it merely sets it going. It is this peculiar kind of chemical 

 re-action that is included under the head of fermentation, and the body which sets up the fermentation 

 is known as a ferment. 



Ferments are of two kinds, soluble ferments, and organized ferments. 



The number of soluble ferments or diastases is very great, and they are formed in a great variety 

 of cells during the course of their development. Their action may be compared' to that of certain of 

 them in the uigestive tubes of animals. They prepare food for absorption. 



The diastase of malt is found in other germina'iug seeds besides barley, and also in starchy roots, 

 like yams, when they are developing leaves. 



Another diastase acts on cane-sugar spliting it up into glucose and levulose. This is called inver- 

 sion of sugar. Cane-sugar is a reserve-material like starch, for although it is capable of diffusion from 

 cell to cell, ii is always changed into glucose when growth is going on. In the beet, for instance, the 

 cane-sugar waich has been stored up in its tissues is transformed in the spring into glucose to be used 

 up in the development of its flowering shoots. The same thing occurs in the stalk of corn (maize) 

 when the fruit is forming, and in sugar-cane when arrowing. These diastatic ferments appear to be 

 formed in the growing parts, and to penetrate from them into the parts where the reserve-materials 

 are stored up. This may be well seen in the germination of the seed of Phytelephas, which is generally 

 known as " vegetable ivory." These seeds are often thrown up by currents on the sea-shore of Jamaica; 

 they are compose! of white cellulose so hard that they are carved in imitation of true ivory, and yet, 

 when the seed is germinating, the delicate tissue of the minute embryo develops a ferment which dis- 

 solves the portion of the hard " ivory" next it. The solution is absorbed and used in growth, and the 

 process continues uutil the whole of the hard seed is used up An exactly similar process takes place 

 in the ge mination of the date-stone. Parasites, such as the fungi which penetrate the hard wood of 

 living trees, doubtless act in the same way. 



Ferments are sum times organized, that is they are living beings and set up fermentation in conse- 

 quence of their development. Of organized ferments, yeast is the most familiar example, and its develop- 

 ment is accompanied by the decomposition of sugar into alcohol, carbonic acid, glycerine, and succinio 

 acid. 



B it to understand better the action of these ferments, we must return to our cultivation of seeds. 

 If we make; a soluti >n of such salts as are commonly found in soils, viz., nitrate of potash, gypsum/ 

 sulpha.e of magne-ia, phosphate of lime, and a trace of salt of iron, and grow seedlings in this solution 

 wuu proper exposure to sunlight, the plant will go through the whole course of its development, pro- 

 duci ig uot only roots and g een leaves, but flowers and seeds. The elements contained in these salts, 

 together with those composing water, and the carbon derived from the carbonic acid in the air, are 

 combined m various proportions to form the substance of the plant. The plant is a chemical laboratory 



