FERMENTATION. 97 



bodies which come into contact with them." This 

 was nothing more than an extension of Willis' and Stahl's 

 view of fermentation ; they held that a ferment is a body 

 which has a peculiar internal motion which is capable of 

 being transmitted from the ferment to a fermentable matter. 

 So fascinating and plausible a theory, of course, received wide 

 recognition, and until Pasteur's admirable demonstrations of 

 his theory of fermentation were made, had received very 

 general acceptance, especially amongst German chemists 

 and biologists. The mechanical theory and the theory of 

 catalytic forces as used in the old sense have now been 

 laid aside, and the vitalist theory expressed in the following 

 words by Turpin : " Fermentation as effect, and vegetation 

 as cause, are two things inseparable in an act of decom- 

 position of sugar " has taken the field against all opponents. 

 This theory is that living organisms build up structures 

 and develop energy from the materials in which they 

 live, and break up by their vital activity, either directly 

 or through a soluble ferment, the sugar in which they 

 grow. In this theory albuminoid material is considered 

 to be necessary for the process of fermentation or decom- 

 position only in so far as it is required for the nutrition 

 of the micro-organism, it being denied that nitrogeneous 

 elements play any such part, as that ascribed to them by 

 Liebig, of producing the molecular motion, which brings 

 about the splitting up of the sugar, by undergoing a spon- 

 taneous decomposition. Albuminoid material, in fact, is 

 merely an accompaniment of the process of fermentation 

 a necessary one, no doubt, but one not in any way playing 

 the part of causal factor. 



What takes place in brewing, a process which, though until 

 recently incompletely understood, has long been carried on 

 on an enormous scale in most northern countries ? Malt is 

 barley in which a certain proportion of the starch of the 

 grain has been converted into sugar by the process known 

 as "malting." This consists essentially in moistening the 

 grain several times, keeping it at a temperature high enough 

 to promote its sprouting, during which a substance called 

 diastase is developed as the result of the vital activity of 

 the cells in the germinating grain which acting on the starch 

 converts it into sugar. As soon as this takes place the 

 sprouting is stopped by raising the temperature and then by 



