Excrement Tubs

Excrement Tubs. — The excrement tubs bate ) 01 the contrary, exert a very energetic action, since they effect a true digestion of the hide, which first of all softens, but which then may deteriorate profoundly if the attack is prolonged too far. Two 

However, whatever is the nature of the bacterial species which here come into play, undoubtedly these act through the enzymes which they secrete, as well as through the ammoniacal products which are formed by their action. Wood found, in fact, that if such a tub in full power is taken and the volatile products are isolated by distillation in a vacuum, and the enzymes by predpitation with alcohol, the liquid which remains has lost all its properties, while the mixture of the two parts previously separated, the amines and the enzymes, exerts a very favorable action on the hide. Another indication that the bacteria do not act so much by their vegetative life as by the products to which they give rise comes from the fact that fresh tubs are without action on tripe, and that it is necessary to cause the excrements 

On the other hand, certain accidents in the use of tubs result from the inopportune development of injurious bacteria which are always found associated with the useful bacteria in tin excrements. Thus a bad preliminary fermentation can favor tlie multiplication of a particular bacterium, which causes the i ro-duction of black tub, whose action on the hide is very disastrous. In the same manner, the undecanted tubs, which, however, are more active than clear tubs, are not to be recommended, because of the harmful bacteria which accumulate in the foul U K Mt and which, by fixing themselves on the hide, may si ot and even pierce it. 

Finally, the enzymes remaining in the excrements at the moment of their expulsion intervene, in their turn, when these tubs are used. Among the proteolytic enzymes which are found there are tr) sin and erepsin. The alkalinity of the medium in which they are placed is very favorable to their activity, and there is no doubt but that they also contribute to the hydrolyas of the complex nitrogenous materials stHl contained in the excrements, and to the preparation of a favorable medium for the development of the useful bacteria of the tubs. 

Schidtz-Dumont. D bourrage a l 6chaufie, Mon. Scient., 1897, p. 312. ScHROEDER et Schmitz-Ddmont. DinglePs, 1896. 

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