Moritz Traube (1826-1894)

On the theory of fermentation and decay phenomena, also of ferment activity in general

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The true cause of the phenomena of fermentation lies in the principles developed in the following, principles partly found on direct experiment partly irrefutably concluded from already known facts:

1. The putrefaction and decay ferments are definite chemical compounds arising from the reaction of the protein substances with water (perhaps with the co-operation of oxygen), arising thus from a chemical process, which we are accustomed to designate shortly putrefaction.

   Little as with the mutability of the ferments a purification is possible, all the facts however show that they in their composition can diverge only little from the protein substances, from the reaction of which with water they originated.

2. The ferments present in the organism likewise have arisen highly probably from the reaction of the protein substances with water (perhaps with the co-operation with oxygen). Only, because formed under special conditions provided in the living organism, they have also other properties than those of the putrefaction ferments formed outside the organism. The Schwann hypothesis, which considers putrefaction and decay as conditioned by lower organisms, by vital processes, must be reversed. That is to say the power depending on the atomic composition of the protein substances to decompose water and to form ferments is also in the organisms the cause of most fermentation processes, of most vital-chemical processes altogether.

3. Amongst the ferments formed inside and outside the organism there are:
   1. Such which are capable to take up merely free oxygen with ease and to hold it only loosely bound. (Decay ferments);

   2. Such which also take up already bound oxygen, that is to say are capable easily to remove oxygen from other bodies. The process of oxygen removal is in most cases the following: the ferment attracts the oxygen of the water to itself, whilst the passive substance, for example indigo or indigo-sulphuric acid, takes up the hydrogen. The water is thus through the action of two mutually supporting affinities broken down to oxygen and hydrogen respectively. (Reduction ferment);

   3. Such ferments which even without participation of a second affinity for the hydrogen are in the state directly to split the water, whereby the hydrogen is freely evolved. These ferments, or this ferment develops in the advanced stage of putrefaction of gluten and caesin. (We call it the highest putrefaction ferment).

4. All these ferments have the power of transferring to other bodies the oxygen taken up in one or the other manner, that is to say to become again reduced by them and to be put into the state to take up new quantities of oxygen, again to transfer it and so on. In this way all ferments may transfer free or bound oxygen to other substances in almost endless amounts, that is to bring about fermentation and decay.