106 THE GERM THEORY OF DISEASE. 



SOLUBLE FERMENTS. 



We have said enough to indicate the mode of action of 

 bacteria in destroying substances in general, and in causing 

 disease. Some forms may possibly cause disease by their 

 presence, by aggregating into groups and causing irritation, 

 like the animal parasites, as the itch mite; but we are per- 

 suaded that their general mode of action is through their 

 soluble ferment and the toxic properties of their waste pro- 

 ducts, to be examined presently. In this manner the hardest 

 substances are made to yield ; are melted down almost as 

 readily as softer materials. Soluble ferments do not depend 

 for their dissolving power upon either acidity or alkalinity. 

 Some are acid, but generally these reactions are not very 

 marked, and normally seem capable of considerable variation. 

 They seem to be Nature's solvents, manufactured by the life 

 force, and used for the maintenance of the creature. We can 

 neither form them, nor tell why they should have such power. 

 We can only examine them, learn their powers, and wonder 

 at Nature's handiwork. 



PATHOLOGICAL FORMATION OF FERMENTS. 



We have reason to believe, at least to suspect, that soluble 

 ferments are often formed in places where they are not wanted. 

 Tissue is stimulated to false secretion by various irritants and 

 in many ways. It is probable that many of the excoriating 

 secretions which we see about the ears, necks, and other parts, 

 in children, are soluble ferments given out through some mal- 

 condition of the tissues. In this manner much harm is accom- 

 plished. We will allude to this again. 



We have reason to suspect that in some cases decay of the 

 teeth may come about in this way. We have already seen 

 that tooth substance is digested and removed by a soluble 

 ferment normally formed. Why is riot the tissue forming a 



